tag:theconversation.com,2011:/id/topics/carbon-nanotubes-569/articlesCarbon nanotubes – The Conversation2022-11-29T13:34:50Ztag:theconversation.com,2011:article/1942382022-11-29T13:34:50Z2022-11-29T13:34:50ZGraphene is a proven supermaterial, but manufacturing the versatile form of carbon at usable scales remains a challenge<figure><img src="https://images.theconversation.com/files/497098/original/file-20221123-22-6q2g12.jpg?ixlib=rb-1.1.0&rect=17%2C34%2C1260%2C770&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Graphene has many incredible physical properties that arise from its one-atom-thick carbon structure.</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Graphen.jpg#/media/File:Graphen.jpg">AlexanderAlUS/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>“Future chips may be <a href="https://www.msn.com/en-us/news/technology/future-chips-may-be-10-times-faster-all-thanks-to-graphene/ar-AA14qqsu">10 times faster, all thanks to graphene</a>”; “Graphene may be <a href="https://www.newswise.com/coronavirus/wonder-material-can-be-used-to-detect-covid-19-quickly-accurately/?article_id=753042">used in COVID-19 detection</a>”; and “Graphene allows batteries to <a href="https://www.theverge.com/22771702/graphene-power-bank-review-price-speed">charge 5x faster</a>” – those are just a handful of recent dramatic headlines lauding the possibilities of graphene. Graphene is an incredibly light, strong and durable material made of a single layer of carbon atoms. With these properties, it is no wonder researchers have been studying ways that graphene could advance material science and technology for decades.</p>
<p>I never know what to expect when I tell people <a href="https://scholar.google.com/citations?user=yykU46oAAAAJ&hl=en&oi=ao">I study graphene</a> – some have never heard of it, while others have seen some version of these headlines and inevitably ask, “So what’s the holdup?” </p>
<p>Graphene is a fascinating material, just as the sensational headlines suggest, but it is only just starting be used in real-world applications. The problem lies not in graphene’s properties, but in the fact that it is still incredibly difficult and expensive to manufacture at commercial scales.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/497095/original/file-20221123-20-ztyacw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A black and white image of a crystalline layer on a surface." src="https://images.theconversation.com/files/497095/original/file-20221123-20-ztyacw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/497095/original/file-20221123-20-ztyacw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=554&fit=crop&dpr=1 600w, https://images.theconversation.com/files/497095/original/file-20221123-20-ztyacw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=554&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/497095/original/file-20221123-20-ztyacw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=554&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/497095/original/file-20221123-20-ztyacw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=697&fit=crop&dpr=1 754w, https://images.theconversation.com/files/497095/original/file-20221123-20-ztyacw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=697&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/497095/original/file-20221123-20-ztyacw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=697&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Pure graphene is a uniform, single-atom-thick crystal of carbon arranged in a hexagonal pattern, as seen in this electron microscope image.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Graphene-TEM.jpg#/media/File:Graphene-TEM.jpg">M.H. Gass/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>What is graphene?</h2>
<p>Graphene is most simply defined as a single layer of carbon atoms bonded together in a hexagonal, sheetlike structure. You can think of pure graphene as a one-layer-thick sheet of carbon tissue paper that happens to be the strongest material on Earth. </p>
<p>Graphene usually comes in the form of a powder made of small, individual sheets that are roughly the diameter of a grain of sand. An individual sheet of graphene is <a href="https://doi.org/10.1126/science.1235126">200 times stronger than an equally thin piece of steel</a>. Graphene is also <a href="https://doi.org/10.1038/nature26160">extremely conductive</a>, holds together at <a href="https://doi.org/10.3367/UFNe.0184.201410c.1045">up to 1,300 degrees Fahrenheit (700 C)</a>, can <a href="https://doi.org/10.1016/j.cej.2019.05.034">withstand acids</a> and is <a href="https://news.mit.edu/2017/3-d-graphene-strongest-lightest-materials-0106">flexible and very lightweight</a>.</p>
<p>Because of these properties, graphene could be extremely useful. The material can be used to <a href="https://www.azonano.com/article.aspx?ArticleID=5468#">create flexible electronics</a> and to <a href="https://www.azocleantech.com/article.aspx?ArticleID=936">purify or desalinate water</a>. And adding just 0.03 ounces (1 gram) of graphene to 11.5 pounds (5 kilograms) of cement <a href="https://firstgraphene.net/applications/concrete/#:%7E:text=The%20use%20of%20graphene%20concrete,new%20generation%20of%20concrete%20designs">increases the strength of the cement by 35%</a>. </p>
<p>As of late 2022, Ford Motor Co., with which I worked as part of my doctoral research, is one of the the only companies to use graphene at industrial scales. Starting in 2018, Ford began making plastic for its vehicles that was 0.5% graphene – <a href="https://media.ford.com/content/fordmedia/fna/us/en/news/2018/10/09/ford-innovates-with-miracle-material-powerful-graphene-for-vehicle-parts.html">increasing the plastic’s strength by 20%</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/497097/original/file-20221123-26-1wxtw5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A close-up photo of the tip of a pencil writing on paper." src="https://images.theconversation.com/files/497097/original/file-20221123-26-1wxtw5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/497097/original/file-20221123-26-1wxtw5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/497097/original/file-20221123-26-1wxtw5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/497097/original/file-20221123-26-1wxtw5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/497097/original/file-20221123-26-1wxtw5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/497097/original/file-20221123-26-1wxtw5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/497097/original/file-20221123-26-1wxtw5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Researchers made the first piece of graphene by peeling layers of carbon off of graphite – or pencil lead – with tape.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/macro-pencil-tip-resting-on-blank-white-paper-royalty-free-image/856908132?phrase=pencil%20lead&adppopup=true">Rapid Eye/E+ via Getty Images</a></span>
</figcaption>
</figure>
<h2>How to make a supermaterial</h2>
<p>Graphene is produced in two principal ways that can be described as either a top-down or bottom-up process.</p>
<p>The world’s <a href="https://www.graphene-info.com/graphene-history-controversy-and-nobel-prize">first sheet of graphene</a> was created in 2004 out of graphite. Graphite, commonly known as pencil lead, is composed of millions of graphene sheets stacked on top of one another. Top-down synthesis, also known as <a href="https://www.azonano.com/article.aspx?ArticleID=5471">graphene exfoliation</a>, works by peeling off the thinnest possible layers of carbon from graphite. Some of the earliest graphene sheets were made by using cellophane tape to <a href="https://science.wonderhowto.com/how-to/make-graphene-sheets-from-graphite-flakes-and-cellophane-tape-402113/">peel off layers of carbon from a larger piece of graphite</a>. </p>
<p>The problem is that the molecular forces holding graphene sheets together in graphite are very strong, and it’s hard to pull sheets apart. Because of this, graphene produced using top-down methods is often many layers thick, has holes or deformations, and <a href="https://doi.org/10.1002/adma.201803784">can contain impurities</a>. Factories can produce a few tons of mechanically or chemically exfoliated graphene per year, and for many applications – like mixing it into plastic – the <a href="https://www.compositesworld.com/articles/graphene-101-forms-properties-and-applications">lower-quality graphene works well</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/497094/original/file-20221123-16-meka9j.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A thin, folded, rough-edged piece of graphene." src="https://images.theconversation.com/files/497094/original/file-20221123-16-meka9j.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/497094/original/file-20221123-16-meka9j.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=420&fit=crop&dpr=1 600w, https://images.theconversation.com/files/497094/original/file-20221123-16-meka9j.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=420&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/497094/original/file-20221123-16-meka9j.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=420&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/497094/original/file-20221123-16-meka9j.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=528&fit=crop&dpr=1 754w, https://images.theconversation.com/files/497094/original/file-20221123-16-meka9j.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=528&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/497094/original/file-20221123-16-meka9j.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=528&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Graphene flakes made from top-down methods are usually more than one atom thick and have impurities like folds and tears, as seen in this image.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Graphene_flakes.JPG#/media/File:Graphene_flakes.JPG">Дагесян Саркис Арменакович/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Top-down, exfoliated graphene is far from perfect, and some applications do need that pristine single sheet of carbon. </p>
<p>Bottom-up synthesis builds the carbon sheets one atom at a time over a few hours. This process – called <a href="https://www.graphenea.com/pages/cvd-graphene#.Y3vcF3bMI2w">vapor deposition</a> – allows researchers to produce high-quality graphene that is one atom thick and up to 30 inches across. This yields graphene with the best possible mechanical and electrical properties. The problem is that with a bottom-up synthesis, it can take <a href="https://doi.org/10.1021/acs.chemrev.8b00325">hours to make even 0.00001 gram</a> – not nearly fast enough for any large scale uses like in <a href="https://doi.org/10.1038/nnano.2010.132">flexible touch-screen electronics or solar panels</a>, for example.</p>
<h2>So what’s the holdup?</h2>
<p>Current production methods of graphene, both top-down and bottom-up, are expensive as well as energy and resource intensive, and simply produce too little product, too slowly. </p>
<p>Some companies do manufacture graphene and sell it for <a href="https://bigthink.com/the-present/flash-graphene/">US$60,000 to $200,000 per ton</a>. There are a limited number of uses that make sense at these high costs.</p>
<p>While small amounts of top-down or bottom-up graphene can satisfy the needs of researchers, for companies even just the process of prototyping a new material, application or manufacturing process requires many pounds of graphene powder or hundreds of graphene sheets and a lot of time and effort. It took significant investment and more than four years of study, development and optimization before graphene hit the production line at Ford. </p>
<p>Current production can barely cover experimentation, much less widespread use. </p>
<h2>Improving manufacturing</h2>
<p>For a material that has been around since only 2004, a lot of progress has been made in scaling up the production and implementation of graphene. </p>
<p>There are hints that graphene is starting to break through at a commercial level. There are a huge number of <a href="https://fortune.com/2020/12/13/what-is-graphene-entrepreneurs-headphones-smartphones-construction-eco-friendly-thinnest-material-on-earth/">graphene-related startups looking at a wide range of uses</a> ranging from <a href="https://nanotechenergy.com/">energy storage</a> to <a href="https://graphmatech.com/">composites</a> to <a href="https://www.inbrain-neuroelectronics.com/">nerve stimulation</a>. Major companies – such as <a href="https://electrek.co/2022/03/22/elon-musk-tesla-working-new-manganese-battery-cell/">Tesla</a>, <a href="https://www.thegraphenecouncil.org/blogpost/1501180/347505/LG-Electronics-Secures-Its-Position-in-CVD-Graphene-Production">LG</a> and <a href="https://www.thegraphenecouncil.org/blogpost/1501180/359799/BASF-Applies-Expertise-to-Graphene-Commercialization">chemical giant BASF</a> – are also investigating how graphene could be used, in rechargeable batteries, flexible or wearable electronics and next-generation materials.</p>
<p>Graphene is ripe for a breakthrough that will bring down the cost and increase the scale of production, and this is an <a href="https://www.phdassistance.com/blog/graphenes-for-research-and-the-growing-number-of-publications-per-year/">area of intense academic research</a>. One new technique discovered in 2020, called <a href="https://doi.org/10.1038/s41586-020-1938-0">flash joule heating</a>, is especially promising. Researchers have shown that passing large amounts of electricity through any carbon source reorganizes the carbon-carbon bonds into a graphene structure. Using this process, it is possible to make many pounds of high-quality graphene for a relatively low cost out of any carbon-containing material like coal or even trash. A <a href="https://www.universalmatter.com/">company called Universal Matter Inc.</a> is already commercializing the process.</p>
<p>Once the cost of graphene comes down, the commercial applications will follow. The <a href="https://www.fortunebusinessinsights.com/graphene-market-102930">appetite for graphene is huge</a>, but it is going to take some time before this material lives up to its potential.</p><img src="https://counter.theconversation.com/content/194238/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kevin Wyss receives funding through the NSF Graduate Research Fellowship, as well as the Rice University Stauffer-Rothrock Fellowship. He has worked in collaboration with Ford Motor Company and Universal Matter, but is not an employee.</span></em></p>Graphene is superstrong and superconductive, and it has applications in everything from construction to electronics. But to date there have been almost no commercial uses of the material.Kevin Wyss, PhD Student in Chemistry, Rice UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1368312020-04-22T18:45:02Z2020-04-22T18:45:02ZA smart second skin gets all the power it needs from sweat<p><em>The Research Brief is a short take about interesting academic work.</em></p>
<h2>The big idea</h2>
<p>Skin is the largest organ of the human body. It conveys a lot of information, including temperature, pressure, pleasure and pain. Electronic skin (e-skin) mimics the properties of biological skin. Recently developed e-skins are capable of wirelessly monitoring physiological signals. They could play a crucial role in the next generation of robotics and medical devices. </p>
<p><a href="http://www.gao.caltech.edu/">My lab at Caltech</a> is interested in studying human biology and monitoring human health by using advanced bioelectronic devices. The e-skin we have developed not only analyzes the chemical and molecular composition of human sweat, it’s <a href="http://robotics.sciencemag.org/lookup/doi/10.1126/scirobotics.aaz7946">fully powered by chemicals in sweat</a>.</p>
<h2>Why it matters</h2>
<p>Existing e-skins and wearable devices primarily focus on monitoring physiological parameters like heart rate and can’t assess health information at the molecular level. Moreover, they typically require batteries to power them, and the batteries need to be recharged frequently.</p>
<p>Despite recent efforts to harvest energy from the human body, there are no reports of self-powered e-skins that are able to perform biosensing and transmit the information via standard Bluetooth wireless communications. This comes down to the lack of power efficiency. There is a need for a self-powered device that can continuously collect molecular as well as physical information and wirelessly transmit the information to other devices.</p>
<h2>How we do this work</h2>
<p>The approach we take to harvesting energy from the human body is based on biofuel cells. Fuel cells convert chemical energy to electricity. The biofuel cells we developed for our e-skin convert the lactic acid in human sweat to electricity. In addition to the biofuel cells, the e-skin contains biosensors that can analyze metabolic information like glucose, urea and pH levels, to monitor for diabetes, ischaemia another health conditions, as well as physical information like skin temperature. The e-skin, made of soft materials and attached to a person’s skin, performs real-time biosensing, powered solely by sweat.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/329621/original/file-20200422-82699-uzmg0b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/329621/original/file-20200422-82699-uzmg0b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=403&fit=crop&dpr=1 600w, https://images.theconversation.com/files/329621/original/file-20200422-82699-uzmg0b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=403&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/329621/original/file-20200422-82699-uzmg0b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=403&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/329621/original/file-20200422-82699-uzmg0b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=506&fit=crop&dpr=1 754w, https://images.theconversation.com/files/329621/original/file-20200422-82699-uzmg0b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=506&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/329621/original/file-20200422-82699-uzmg0b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=506&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The sweat-powered biofuel cells in this electronic skin provide enough electricity to power biological sensors and transmit the information wirelessly to other devices.</span>
<span class="attribution"><span class="source">Yu et al., Sci. Robot. 5, eaaz7946 (2020)</span></span>
</figcaption>
</figure>
<p>Previously developed wearable biofuel cells <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/elan.201600019">don’t produce a lot of power</a> and aren’t very stable. We greatly improved the power output and stability of the biofuel cells by using novel nanomaterials for the cell’s two electrodes. The cathode of our biofuel cell is composed of a mesh of carbon nanotubes decorated with nanoparticles containing platinum and cobalt. The anode is a nanocomposite material that contains an enzyme that breaks down lactic acid. </p>
<p>The biofuel cells can generate a continuous, stable output as high as several milliwatts per square centimeter over multiple days in human sweat. That’s enough to power the biosensors as well as wireless communication. We demonstrated our e-skin by monitoring glucose, pH, ammonium ions and urea levels in studies using human subjects. We also used our e-skin as a human-machine interface to control the motion of a robotic arm and a prosthetic leg.</p>
<h2>What’s next</h2>
<p>We plan to further improve the power output of the biofuel cells and integrate different biosensors. The development of fully self-powered e-skin opens the door to numerous robotic and wearable health care possibilities. Wearable sensor arrays could be used for health monitoring, early disease diagnosis and potentially nutritional intervention. In addition, self-powered e-skin could be used to design and optimize next generation prosthetics.</p>
<p>[<em>Deep knowledge, daily.</em> <a href="https://theconversation.com/us/newsletters?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=deepknowledge">Sign up for The Conversation’s newsletter</a>.]</p><img src="https://counter.theconversation.com/content/136831/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Wei Gao receives funding from the National Institute of Health. </span></em></p>Lightweight, flexible materials can be used to make health-monitoring wearable devices, but powering the devices is a challenge. Using fuel cells instead of batteries could make the difference.Wei Gao, Assistant Professor of Medical Engineering, California Institute of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1000372019-06-17T13:10:30Z2019-06-17T13:10:30ZBlack plastic can’t be recycled – but we’ve just found a way to use the carbon in renewable energy<figure><img src="https://images.theconversation.com/files/279766/original/file-20190617-118514-7ss212.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/healthy-food-delivery-take-away-diet-1420252514?studio=1">Goskova Tatiana/Shutterstock</a></span></figcaption></figure><p>The big problem with plastics is that though they last for a very long time, most are thrown away after only one use. <a href="http://advances.sciencemag.org/content/3/7/e1700782">Since plastics were invented</a> in the 1950s, about 8,300m metric tonnes (Mt) have been made, but over half (4,900 Mt) is already in landfill or has been lost to the environment. In 2010 alone, an estimated <a href="https://www.policyconnect.org.uk/research/plastic-packaging-plan-achieving-zero-waste-exports">4.8 to 12.7 Mt went into the oceans</a>.</p>
<p>Only <a href="http://www.bpf.co.uk/sustainability/plastics_recycling.aspx">a small proportion</a> of the hundreds of types of plastics can be recycled by conventional technology. But there are other things we can do to reuse plastics after they’ve served their original purpose. My research, for example, focuses on chemical recycling, and I’ve been looking into how food packaging can be used to create new materials like wires for electricity.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/why-cant-all-plastic-waste-be-recycled-100857">Why can't all plastic waste be recycled?</a>
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</em>
</p>
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<p>In chemical recycling you use the constituent elements to make new materials. All plastics are made of carbon, hydrogen and sometimes oxygen. The amounts and arrangements of these three elements make each plastic unique. As plastics are very pure and highly refined chemicals, they can be broken down into these elements and then bonded in different arrangements to make high value materials such as carbon nanotubes. In theory, the only side products from doing this should be oxygen and hydrogen.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-we-can-turn-plastic-waste-into-green-energy-104072">How we can turn plastic waste into green energy</a>
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</em>
</p>
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<p>Carbon nanotubes are tiny molecules with <a href="https://www.zdnet.com/article/5-surprising-uses-for-carbon-nanotubes/">incredible physical properties</a>. Think of a piece of chicken wire wrapped into a cylinder. This is what the structure of a carbon nanotube looks like. When carbon is arranged like this it can conduct both heat and electricity. These two different forms of energy are each very important to control and use in the right quantities, depending on your needs. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/279584/original/file-20190614-158967-wc79q0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/279584/original/file-20190614-158967-wc79q0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/279584/original/file-20190614-158967-wc79q0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/279584/original/file-20190614-158967-wc79q0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/279584/original/file-20190614-158967-wc79q0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/279584/original/file-20190614-158967-wc79q0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/279584/original/file-20190614-158967-wc79q0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/279584/original/file-20190614-158967-wc79q0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Tiny, hollow carbon nanotubes have incredible strength.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/carbon-nanotube-3d-rendering-1094554436?src=bFwkndIs7UVMPwJ5YEd6vA-1-38&studio=1">woverwolf/Shutterstock</a></span>
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<p>For <a href="https://www.mdpi.com/2311-5629/5/2/32">our new study</a>, we took plastics – in particular <a href="https://www.greenpeace.org.uk/blackplastic/">black plastics</a>, which are commonly used as packaging for ready meals and <a href="https://www.theguardian.com/environment/2018/sep/21/lidl-to-stop-using-black-plastic-fruit-and-vegetable-packaging">fruit and vegetables in supermarkets</a>, but <a href="https://metro.co.uk/2018/06/10/know-black-plastic-cant-recycled-7619361/">can’t be easily recycled</a> – and stripped the carbon from them, then built nanotube molecules from the <a href="https://www.zyvex.com/nanotech/feynman.html">bottom up</a> using the carbon atoms.</p>
<p>Nanotubes are 80,000 times thinner than a human hair, in fact they are virtually as thin as DNA strands. But being made of carbon-carbon bonds also gives them diamond-like strength. They are so strong they’re considered the ideal material for a proposed <a href="https://futurism.com/the-byte/space-elevator-carbon-nanotube-fiber">space elevator</a>.</p>
<p>Nanotubes have already been used to make conductive films on <a href="https://www.fraunhofer.de/en/press/research-news/2011/january/Touchscreen_Made_of_Carbon.html">touchscreen displays</a>, and their pliability has made them ideal for <a href="https://www.technologyreview.com/s/532906/nanobuds-could-turn-almost-any-surface-into-a-touch-sensor/">flexible electronics</a> too. They have also been used to develop fabrics that <a href="https://www.ibtimes.co.uk/clothes-future-could-generate-their-own-electricity-using-carbon-nanotube-based-generators-1636937">create energy when you move</a>, and NASA has used them to <a href="https://sciencebusiness.technewslit.com/?p=5519">prevent electric shocks</a> on the Juno spacecraft. In addition, they were recently used to create <a href="https://aip.scitation.org/doi/full/10.1063/1.5093327">antennas for 5G networks</a>.</p>
<h2>New use for nanotubes</h2>
<p>We’ve been specifically making carbon nanotubes because they can be used to solve the problem of electricity cables overheating and failing. <a href="https://data.worldbank.org/indicator/eg.elc.loss.zs">Across the world</a> about 8% of electricity is lost in transmission and distribution. This might not seem like much, but it is low because electricity cables are short, which means that power stations have to be close to the location where electricity is used, otherwise the energy is lost in transmission. Many long range cables (which are made of metals) can’t operate at full capacity because they would overheat and melt. This is a real problem for a renewable <a href="https://www.cambridge.org/core/journals/mrs-bulletin/article/future-global-energy-prosperity-the-terawatt-challenge/68700B4060358F79807A51C867905836">energy future</a> using <a href="https://www.globalwindatlas.info/">wind</a> or <a href="https://globalsolaratlas.info/">solar</a>, because the best sites are far from where people live.</p>
<p>I’ve spent several years learning what’s important to get the best electrical performance from <a href="https://pubs.acs.org/doi/abs/10.1021/acs.nanolett.7b03390">carbon wires</a>. To do this I first specialised in creating the <a href="https://pubs.rsc.org/en/content/articlelanding/2013/nr/c3nr03142j/unauth">highest quality nanotubes</a> using the most appropriate <a href="https://pubs.acs.org/doi/abs/10.1021/nl201315j">methods</a> to make best the conductor. I mapped out the <a href="https://pubs.rsc.org/en/content/articlelanding/2013/ta/c3ta13543h/unauth">best reaction conditions</a> which gave us the ability to use black plastics as a feedstock. </p>
<p>Now we have been able to use nanotubes to transmit <a href="https://www.mdpi.com/2311-5629/5/2/32/htm#fig_body_display_carbon-05-00032-f003">electricity to a light bulb</a> in a small demonstrator model. In the long run I plan to make high purity carbon electrical cables using waste plastic materials. And I am currently working to improve the nanotube material’s electrical performance and increase the output, so they are ready for large-scale deployment in the next three years. </p>
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Read more:
<a href="https://theconversation.com/we-can-turn-co-sub-2-sub-in-the-air-into-new-materials-but-dont-expect-that-to-stop-climate-change-46429">We can turn CO<sub>2</sub> in the air into new materials – but don't expect that to stop climate change</a>
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<p>Sticking to my motto of “no carbon left behind” we are also developing news ways to quickly and economically convert plastics using this chemical recycling method. Any carbon that escapes our process is a loss to us, and could be a pollutant. So we aim to keep this to an absolute minimum by capturing the carbon after each step using chemical scrubbers to capture carbon from the exhaust gas so it can be upcycled again and again, until we’ve used as much of the original carbon as physically possible.</p>
<p>We are also looking at using other forms of carbon waste to make nanomaterials. Plastics are a known problem, but there are lots of other carbon materials such as tyres, papers, paints, solvents, and refrigerants that don’t always have an end of life plan. The plastics problem is <a href="https://www.bbc.co.uk/news/science-environment-42264788">growing at the rate of plastic use</a>, with only a very small amount of them being reused. But our research shows that we can use today’s problem to make tomorrow’s materials.</p><img src="https://counter.theconversation.com/content/100037/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dr Alvin Orbaek White is funded by a Sêr Cymru II Fellowship that is supported by the Welsh Government and the European Union Regional Development Fund (ERDF). The funding is used to investigate the science of carbon nanotubes. He is also the founder of Trimtabs Ltd, a new science and technology firm dedicated to environmental impact.</span></em></p>A nanotube innovation using waste plastic could help solve one of the world’s energy problems.Alvin Orbaek White, Senior Lecturer in Engineering and Sêr Cymru II Fellow, Swansea UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/605972016-10-21T01:45:50Z2016-10-21T01:45:50ZThe next frontier in medical sensing: Threads coated in nanomaterials<figure><img src="https://images.theconversation.com/files/142056/original/image-20161017-12463-1t71g90.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A hydro-responsive thread can be used with sensors to monitor body functions.</span> <span class="attribution"><span class="source">Alonso Nichols, Tufts University</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Doctors have various ways to assess your health. For example, they <a href="http://dx.doi.org/10.1016/j.amjmed.2015.11.039">measure your heart rate and blood pressure</a> to indirectly assess your heart function, or straightforwardly <a href="http://dx.doi.org/10.1111/j.1537-2995.2012.03784.x">test a blood sample for iron content</a> to diagnose anemia. But there are plenty of situations in which that sort of monitoring just isn’t possible. </p>
<p>To test the <a href="https://www.researchgate.net/profile/Viktor_Lindgren/publication/268787806_Deep_infection_after_total_hip_replacement_a_method_for_national_incidence_surveillance/links/5488b0540cf2ef344790a330.pdf">health of muscle and bone in contact with a hip replacement</a>, for example, requires a complicated – and expensive – procedure. And if problems are found, it’s often too late to truly fix them. The same is true when dealing with deep wounds or internal incisions from surgery.</p>
<p>In <a href="http://nanolab.ece.tufts.edu/">my engineering lab at Tufts University</a>, we asked ourselves whether we could make sensors that could be seamlessly embedded in body tissue or organs – and yet could communicate to monitors outside the body in real time. The first concern, of course, would be to make sure that the materials wouldn’t cause infection or an immune response from the body. The sensors would also need to match the mechanical properties of the body part they would be embedded in: soft for organs and stretchable for muscle. And, ideally, they would be relatively inexpensive to make in large quantities.</p>
<p>Our search for materials we might use led us to a surprising candidate – threads, just like what our clothes are made of. Thread has many advantages. It is abundant, easy to make and very inexpensive. Threads can be made flexible and stretchable – and even from materials that aren’t rejected by the body. In addition, doctors are very comfortable working with threads: They routinely use sutures to stitch up open wounds. What if we could <a href="http://dx.doi.org/10.1038/micronano.2016.39">embed sensor functions into threads</a>?</p>
<h2>Finding the right sensor</h2>
<p>Today’s medical sensors are typically rigid and flat – which limits them to monitoring surfaces such as the scalp or skin. But most organs and tissues are three-dimensional heterogeneous multilayered biological structures. To monitor them, we need something much more like a thread.</p>
<p>Nanomaterials can be organic or inorganic, inert or bioactive, and can be designed with physical and chemical properties that are useful for medical sensing. For example, carbon nanotubes are amazingly versatile – their <a href="http://dx.doi.org/10.1002/adfm.201302344">electrical conductivity can be customized</a>, which has led to them being the basis of the next generation of sensors and electronic transistors. They can even <a href="http://dx.doi.org/10.1021/ja4000917">detect single molecules</a> of DNA and proteins. The <a href="http://dx.doi.org/10.1039/C2EE24203F">organic nanomaterial polyaniline</a> has a similarly broad range of applications, notably its conductivity depends on the strength of the acid or base it is in contact with.</p>
<h2>Making the materials</h2>
<p>To make sensing threads, we start with cotton and other conventional threads, dip them in liquids containing different nanomaterials, and rapidly dry them. Depending on the properties of the nanomaterial we use, these can monitor mechanical or chemical activity. </p>
<p>For example, coating stretchable rubber fiber with carbon nanotubes and silicone can make threads that can sense and measure physical strain. As they stretch, the threads’ electrical properties change in ways we can monitor externally. This can be used to monitor wound healing or muscle strain experienced due to artificial implants. After an implant, abnormal strain could be a sign of slow healing, or even improper placement of the device. Threads monitoring strain levels can send a message to both patient and doctor so that treatment can be modified appropriately.</p>
<p>Monitoring the electricity flow between one cotton thread coated with carbon nanotubes and polyaniline nanofibers, and another coated with silver and silver chloride, allows us to measure acidity, which can be a sign of infection.</p>
<p>To help people who need to monitor their blood sugar levels, we can coat a thread with <a href="http://dx.doi.org/10.1016/j.bios.2012.06.045">glucose oxidase</a>, which reacts with glucose to generate an electrical signal indicating how much sugar is in the patient’s blood. Similarly, coating conductive threads with other nanomaterials sensitive to specific elements or chemicals can help doctors measure potassium and sodium levels or other metabolic markers in your blood.</p>
<h2>Multiple uses</h2>
<p>Beyond sensing abilities, many thread materials, such as cotton, have another useful property: wicking. They can move liquid along their length via capillary action without needing a pump, the way <a href="http://dx.doi.org/10.1007/BF02896314">melted wax flows up a candlewick</a> to feed the flame.</p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/142057/original/image-20161017-12443-1ru1h1i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/142057/original/image-20161017-12443-1ru1h1i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/142057/original/image-20161017-12443-1ru1h1i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=233&fit=crop&dpr=1 600w, https://images.theconversation.com/files/142057/original/image-20161017-12443-1ru1h1i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=233&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/142057/original/image-20161017-12443-1ru1h1i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=233&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/142057/original/image-20161017-12443-1ru1h1i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=293&fit=crop&dpr=1 754w, https://images.theconversation.com/files/142057/original/image-20161017-12443-1ru1h1i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=293&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/142057/original/image-20161017-12443-1ru1h1i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=293&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Liquid flowing in threads sutured into skin.</span>
<span class="attribution"><span class="source">Nano Lab, Tufts University</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
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<p>We used cotton threads to transport <a href="http://dx.doi.org/10.1152/physrev.00037.2011">interstitial fluid</a>, which fills in the gaps between cells, from the places it normally exists toward sensing threads located elsewhere. The sensing threads send their electronic signals to an external device housed in a flexible patch, along with a button battery and a small antenna. There, the signals are amplified, digitized and transmitted wirelessly to a smartphone or any Wi-Fi connected device.</p>
<p>These transport-sensing measuring-transmission systems are so small that they can be powered with a tiny battery sitting on top of the skin or could <a href="http://dx.doi.org/10.1016/j.cej.2014.11.011">get energy from glucose</a> in the patient’s blood. That could allow doctors to keep a continuous eye on patients’ health remotely and unobtrusively. </p>
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<a href="https://images.theconversation.com/files/142036/original/image-20161017-12447-1sm1nam.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/142036/original/image-20161017-12447-1sm1nam.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/142036/original/image-20161017-12447-1sm1nam.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=520&fit=crop&dpr=1 600w, https://images.theconversation.com/files/142036/original/image-20161017-12447-1sm1nam.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=520&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/142036/original/image-20161017-12447-1sm1nam.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=520&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/142036/original/image-20161017-12447-1sm1nam.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=653&fit=crop&dpr=1 754w, https://images.theconversation.com/files/142036/original/image-20161017-12447-1sm1nam.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=653&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/142036/original/image-20161017-12447-1sm1nam.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=653&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Smart threads can monitor wounds using a suite of physical and chemical sensors made using threads and passing information to a skin-surface transmitter.</span>
<span class="attribution"><a class="source" href="https://now.tufts.edu/news-releases/researchers-invent-smart-thread-collects-diagnostic-data-when-sutured-tissue">Nano Lab, Tufts University</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p>This type of integrated, wireless monitoring has several advantages over current systems. First, the patient can move around freely, rather than being confined to a hospital bed. In addition, real-time data-gathering provides much more accurate information than periodic testing at a hospital or doctor’s office. And it reduces the cost of health care by moving treatment, monitoring and diagnosis out of the hospital.</p>
<p>So far our testing of nano-infused threads has been in sterile lab environments in rodents. The next step is to perform more tests in animals, particularly to monitor how well the threads do in living tissue over long periods of time. Then we’d move toward testing in humans. </p>
<p>Now that we’ve begun exploring the possibilities of threads, potential uses seem to be everywhere. Diabetic patients can have trouble with <a href="http://dx.doi.org/10.1242/dmm.012237">wounds resisting healing</a>, which can lead to infection, and even amputation. A few choice stitches using sensing threads could let doctors detect these problems at extremely early stages – much sooner than we can today – and take action to prevent them from worsening. Sensing threads can even be woven into bandages, wound dressings or hospital bed sheets to monitor patients’ progress, and raise alarms before problems get out of control.</p><img src="https://counter.theconversation.com/content/60597/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sameer Sonkusale currently receives funding from National Science Foundation and Department of Defense.</span></em></p>Flexible, easy to make, inexpensive, stretchable and simple to coat with nanomaterials, threads are also very commonly used by doctors already.Sameer Sonkusale, Professor of Electrical and Computer Engineering, Tufts UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/568892016-03-29T10:08:42Z2016-03-29T10:08:42ZWe don’t talk much about nanotechnology risks anymore, but that doesn’t mean they’re gone<figure><img src="https://images.theconversation.com/files/116529/original/image-20160328-17824-d98u5v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Vantablack is the darkest pigment ever – thanks to carbon nanotubes.</span> <span class="attribution"><a class="source" href="http://www.surreynanosystems.com/media/images-videos">Surrey NanoSystems</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Back in 2008, carbon nanotubes – exceptionally fine tubes made up of carbon atoms – were <a href="http://www.nytimes.com/2008/05/21/science/21nano.html">making headlines</a>. A new study from the U.K. had just shown that, under some conditions, these <a href="http://dx.doi.org/10.1038/nnano.2008.111">long, slender fiber-like tubes could cause harm</a> in mice in the same way that some asbestos fibers do.</p>
<p>As a collaborator in that study, I was at the time heavily involved in exploring the risks and benefits of novel nanoscale materials. Back then, there was intense interest in understanding how materials like this could be dangerous, and how they might be made safer.</p>
<p>Fast forward to a few weeks ago, when carbon nanotubes were <a href="http://qz.com/630908/the-worlds-blackest-color-belongs-to-one-person-and-hes-instagramming-his-victory/">in the news again</a>, but for a very different reason. This time, there was outrage not over potential risks, but because the artist Anish Kapoor had been given exclusive rights to a carbon nanotube-based pigment – claimed to be one of the blackest pigments ever made.</p>
<p>The worries that even nanotech proponents had in the early 2000s about possible health and environmental risks – and their impact on investor and consumer confidence – seem to have evaporated. </p>
<p>So what’s changed?</p>
<h2>Carbon nanotube concerns, or lack thereof</h2>
<p>The pigment at the center of the Kapoor story is a material called <a href="http://www.surreynanosystems.com/vantablack/vantablack-s-vis">Vantablack S-VIS</a>, developed by the British company Surrey NanoSystems. It’s a <a href="http://www.gizmag.com/vantablack-s-vis-spray/42298/">carbon nanotube-based spray paint</a> so black that surfaces coated with it reflect next to no light.</p>
<p>The original <a href="http://www.surreynanosystems.com/vantablack">Vantablack</a> was a specialty carbon nanotube coating designed for use in space, to reduce the amount of stray light entering space-based optical instruments. It was this far remove from any people that made Vantablack seem pretty safe. Whatever its toxicity, the chances of it getting <a href="http://2020science.org/2014/07/16/safe-worlds-darkest-carbon-nanotube-material/">into someone’s body were vanishingly small</a>. It wasn’t nontoxic, but the risk of exposure was minuscule.</p>
<p>In contrast, Vantablack S-VIS is designed to be used where people might touch it, inhale it, or even (unintentionally) ingest it.</p>
<p>To be clear, Vantablack S-VIS is not comparable to asbestos – the carbon nanotubes it relies on are too short, and too tightly bound together to behave like needle-like asbestos fibers. Yet its combination of novelty, low density and high surface area, together with the possibility of human exposure, still raise serious risk questions. </p>
<p>For instance, as an expert in nanomaterial safety, I would want to know how readily the spray – or bits of material dislodged from surfaces – can be inhaled or otherwise get into the body; what these particles look like; what is known about how their size, shape, surface area, porosity and chemistry affect their ability to damage cells; whether they can act as “Trojan horses” and carry more toxic materials into the body; and what is known about what happens when they get out into the environment.</p>
<p>These are all questions that are highly relevant to understanding whether a new material might be harmful if used inappropriately. And yet they’re notable in their absence in media coverage around the Vantablack S-VIS. The original use was seemingly safe and got people wondering about impacts. The new use appears more risky and yet hasn’t started conversations around safety. What happened to public interest in possible nanotech risks?</p>
<h2>Federal funding around nanotech safety</h2>
<p>By 2008, the U.S. federal government was <a href="http://www.nano.gov/node/239">plowing nearly US$60 million a year</a> into researching the health and environmental impacts of nanotechnology. This year, U.S. federal agencies are <a href="http://www.nano.gov/node/1326">proposing to invest $105.4 million</a> in research to understand and address potential health and environmental risks of nanotechnology. This is a massive 80 percent increase compared to eight years ago, and reflects ongoing concerns that there’s still a lot we don’t know about the <a href="https://www.niehs.nih.gov/research/supported/exposure/nanohealth/index.cfm">potential risks of purposely designed and engineered nanoscale materials</a>.</p>
<p>It could be argued that maybe investment in nanotechnology safety research has achieved one of its original intentions, by boosting public confidence in the safety of the technology. Yet ongoing research suggests that, even if public concerns have been allayed, privately they are still very much alive.</p>
<p>I suspect the reason for lack of public interest is simple. It’s more likely that nanotechnology safety isn’t hitting the public radar because journalists and other commentators just don’t realize they should shining a spotlight on it. </p>
<h2>Responsibility around risk</h2>
<p>With the U.S.’s current level of investment, it seems reasonable to assume there are many scientists across the country who know a thing or two about nanotechnology safety. And who, if confronted with an application designed to spray carbon nanotubes onto surfaces that might subsequently be touched, rubbed or scraped, might hesitate to give it an unqualified thumbs up.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/116531/original/image-20160328-17849-1j0xq6o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/116531/original/image-20160328-17849-1j0xq6o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/116531/original/image-20160328-17849-1j0xq6o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=900&fit=crop&dpr=1 600w, https://images.theconversation.com/files/116531/original/image-20160328-17849-1j0xq6o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=900&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/116531/original/image-20160328-17849-1j0xq6o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=900&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/116531/original/image-20160328-17849-1j0xq6o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1131&fit=crop&dpr=1 754w, https://images.theconversation.com/files/116531/original/image-20160328-17849-1j0xq6o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1131&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/116531/original/image-20160328-17849-1j0xq6o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1131&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Let’s hear what the researchers know and are concerned about.</span>
<span class="attribution"><a class="source" href="http://www.surreynanosystems.com/media/images-videos">Surrey NanoSystems</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Yet in the case of Vantablack S-VIS, there’s been a conspicuous absence of such nanotechnology safety experts in media coverage.</p>
<p>This lack of engagement isn’t too surprising – publicly commenting on emerging topics is something we rarely train, or even encourage, our scientists to do.</p>
<p>And yet, where technologies are being commercialized at the same time their safety is being researched, there’s a need for clear lines of communication between scientists, users, journalists and other influencers. Otherwise, how else are people to know what questions they should be asking, and where the answers might lie?</p>
<p>In 2008, initiatives existed such as those at the <a href="http://cben.rice.edu/">Center for Biological and Environmental Nanotechnology (CBEN)</a> at Rice University and the <a href="http://www.nanotechproject.org/">Project on Emerging Nanotechnologies (PEN)</a> at the Woodrow Wilson International Center for Scholars (where I served as science advisor) that took this role seriously. These and similar programs worked closely with journalists and others to ensure an informed public dialogue around the safe, responsible and beneficial uses of nanotechnology.</p>
<p>In 2016, there are no comparable programs, to my knowledge – both CBEN and PEN came to the end of their funding some years ago.</p>
<p>This, I would argue, needs to change. Developers and consumers alike have a greater need than ever to know what they should be asking to ensure responsible nanotech products, and to avoid unanticipated harm to health and the environment.</p>
<p>Some of the onus here lies with scientists themselves to make appropriate connections with developers, consumers and others. But to do this, they need the support of the institutions they work in, as well as the organizations who fund them. This is not a new idea – there is of course a long and ongoing debate about how to <a href="https://theconversation.com/public-universities-must-do-more-the-public-needs-our-help-and-expertise-56016">ensure academic research can benefit ordinary people</a>.</p>
<p>Yet the fact remains that new technologies all too easily slip under the radar of critical public evaluation, simply because few people know what questions they should be asking about risks and benefits.</p>
<p>Talking publicly about what’s known and what isn’t about potential risks – and the questions that people might want to ask – goes beyond maintaining investor and consumer confidence which, to be honest, depends more on a <em>perception</em> of safety rather than actual dealing with risk. Rather, it gets to the very heart of what it means to engage in socially responsible research and innovation.</p><img src="https://counter.theconversation.com/content/56889/count.gif" alt="The Conversation" width="1" height="1" />
<h4 class="border">Disclosure</h4><p class="fine-print"><em><span>Andrew Maynard has previously received funding from from the National Institutes of Health on nanomaterial safety research. He was previously Chief Science Advisor to the Project on Emerging Nanotechnologies. </span></em></p>Two very similar new carbon nanotube products, released eight years apart, provoked very different reactions. What’s changed about the way we consider nanotechnology risks and benefits?Andrew Maynard, Director, Risk Innovation Lab, Arizona State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/464292015-08-25T13:04:05Z2015-08-25T13:04:05ZWe can turn CO in the air into new materials – but don’t expect that to stop climate change<figure><img src="https://images.theconversation.com/files/92813/original/image-20150824-17762-1iw3cgf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>What if there were a way to suck carbon dioxide right out of the air and turn it into useful products? It might seem fantastic but scientists have actually proved it’s possible. One of the challenges with making it a viable process, however, is manufacturing products that are valuable enough to cover the high costs of extracting the carbon dioxide.</p>
<p>Some excellent new research has raised the possibility of a breakthrough in this area by using CO<sub>2</sub> directly captured from the air to produce a type of graphene, the two-dimensional form of carbon often described as a “<a href="http://www.acs.org/content/acs/en/education/resources/highschool/chemmatters/past-issues/archive-2012-2013/graphene.html">wonder material</a>”. But reported claims that this amounts to producing “<a href="http://www.engadget.com/2015/08/20/carbon-from-the-air/">diamonds from the sky</a>” are somewhat misleading.</p>
<p>There is already a significant market for CO<sub>2</sub> and products made from it, most obviously fertiliser and fuels. This process of treating the gas as a feedstock rather than a waste product is known as carbon dioxide utilisation (CDU) and usually starts by capturing CO<sub>2</sub> from industrial flue gases – exhaust from furnaces or fuel-powered generators.</p>
<h2>Drop in the ocean</h2>
<p>In 2012, carbon dioxide utilisation accounted for <a href="http://www.sciencedirect.com/science/article/pii/S2212982013000322">180 megatonnes of CO<sub>2</sub></a> that would otherwise have gone into the atmosphere, and this has been forecast to rise to 256 megatonnes in 2016. But total global greenhouse gas emissions are around 35 gigatonnes and rising, meaning other emission-reduction strategies such as energy efficiency and renewable power currently play a <a href="http://journal.frontiersin.org/article/10.3389/fenrg.2015.00008/abstract">much larger role</a>.</p>
<p>Sucking CO<sub>2</sub> directly from the air can be a trickier process compared to more concentrated sources such as flue gases. As CO<sub>2</sub> represents just 0.04% of the atmosphere, you have to treat very large amounts of air just to produce even modest quantities of the gas. However, <a href="http://airfuelsynthesis.com">several companies</a> have managed to design chemical processes that are more efficient than those used in flue gas capture and produce enough <a href="http://www.climeworks.com/">industrial CO<sub>2</sub></a> to be economically viable.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/92815/original/image-20150824-17765-ev7w68.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/92815/original/image-20150824-17765-ev7w68.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=458&fit=crop&dpr=1 600w, https://images.theconversation.com/files/92815/original/image-20150824-17765-ev7w68.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=458&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/92815/original/image-20150824-17765-ev7w68.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=458&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/92815/original/image-20150824-17765-ev7w68.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=576&fit=crop&dpr=1 754w, https://images.theconversation.com/files/92815/original/image-20150824-17765-ev7w68.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=576&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/92815/original/image-20150824-17765-ev7w68.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=576&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Carbon nanofibres: cylindrical layers of graphene.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Timeline_of_carbon_nanotubes#/media/File:FlyingThroughNanotube.png">Wikimedia Commons/Magnus Manske</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>The <a href="http://pubs.acs.org/doi/abs/10.1021/acs.nanolett.5b02427">new research</a> from George Washington University in the US demonstrates a way to directly capture CO<sub>2</sub> from the air and turn it into carbon nanofibres, powered just by a few volts of solar electricity and solar heat. These smaller-than-microscopic structures are effectively irregular cylinders made from layers of graphene and can be used to strengthen materials for building aircraft, wind turbines and even sports equipment.</p>
<p>The researchers claim their new manufacturing method is much cheaper than existing techniques and so could open up new uses for the nanofibres. If they can scale the process up to the level of mass production and keep it cost-effective, this would really help grow the market. But a robust life-cycle analysis is needed to substantiate these claims.</p>
<p>If the technique does prove to be a cheap way of mass-producing carbon nanofibres, could it become so widely used that it significantly reduces atmospheric CO<sub>2</sub> levels, a claim <a href="http://www.technologyreview.com/news/540706/researcher-demonstrates-how-to-suck-carbon-from-the-air-make-stuff-from-it/">attributed to the authors</a> (but not in the peer-reviewed paper)? Current production of carbon nanofibres is around <a href="http://bit.ly/1JwBoXt">500 tonnes a year</a> and predicted to increase to around <a href="http://www.cnt-ltd.co.uk/services-events/market-reports/production-and-application-of-carbon-nanotubes-carbon-nanofibers-fullerenes-graphene-and-nanodiamonds-a-global-technology-survey-and-market-analysis/">10,000 tonnes a year</a>. But this is still far from the hundreds of millions of tonnes that would be needed to make a meaningful contribution to greenhouse gas levels.</p>
<h2>Starting point</h2>
<p>It is difficult to see at this time how a market for carbon nanofibres could develop to these levels. One exception might be if the price of nanofibres became so low we could start using it to cost-effectively strengthen building materials. This would also provide an interesting addition to current techniques that turn CO<sub>2</sub> and other chemicals and waste products <a href="http://www.theengineer.co.uk/in-depth/analysis/solid-as-a-rock-mineralising-carbon-dioxide/1008376.article">into stable solids</a>.</p>
<p>Developing viable direct air capture techniques is a major research challenge that will hopefully one day have far-reaching impact. It could help make CO<sub>2</sub> a resource that is available anywhere in the world where a capture unit can be installed. Carbon nanofibres will play a part in the portfolio of technologies that make up carbon dioxide utilisation, again an area that is growing in application and promise.</p>
<p>Sadly it’s most unlikely this interesting breakthrough will be scaled up to limit climate change in the way that has been claimed. We believe that due to the size of the potential market, carbon nanofibres alone will not be able to make a significant impact on CO<sub>2</sub> mitigation. However, many transformative technologies and materials start with a niche area before moving into more mainstream uses. And perhaps this could be the case for direct air capture nanofibres. After all, change has to start somewhere.</p><img src="https://counter.theconversation.com/content/46429/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Peter Styring receives funding from EPSRC, BBSRC, European Commission</span></em></p><p class="fine-print"><em><span>Grant Wilson is a researcher with the European Smart CO2 Transformation project. <a href="http://www.scotproject.org">www.scotproject.org</a></span></em></p><p class="fine-print"><em><span>Katy Armstrong receives funding from EPSRC and European Commission.</span></em></p><p class="fine-print"><em><span>George Dowson receives funding from EPSRC</span></em></p>A new method for creating a form of graphene with carbon dioxide sucked from the air has been announced with misleading claims.Peter Styring, Professor of Chemical Engineering & Chemistry, University of SheffieldGrant Wilson, Research Associate, Environmental and Energy Engineering Research Group, Chemical and Biological Engineering, University of SheffieldKaty Armstrong, CO2Chem Network Manager, University of SheffieldLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/448352015-08-24T19:41:26Z2015-08-24T19:41:26ZBig questions about risk assessment of nanomaterials<figure><img src="https://images.theconversation.com/files/92510/original/image-20150820-32447-eri4fy.jpg?ixlib=rb-1.1.0&rect=177%2C367%2C1729%2C879&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Substances, such as these carbon nanotubes, can behave differently at the nano-scale, and may post a health risk.</span> <span class="attribution"><span class="source">ZEISS Microscopy/Flickr</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>When it comes to nanotechnology, Australians have shown <a href="http://industry.gov.au/industry/IndustrySectors/nanotechnology/Publications/Documents/Emergingtechstudynano.docx">strong support</a> for regulation and safety testing. </p>
<p>One common way of deciding whether and how nanomaterials should be regulated is to conduct a <a href="https://en.wikipedia.org/wiki/Risk_assessment">risk assessment</a>. This involves calculating the risk a substance or activity poses based on the associated hazards or dangers and the level of exposure to people or the environment.</p>
<p>However, our <a href="http://onlinelibrary.wiley.com/doi/10.1111/ropr.12129/abstract">recent review</a> found some serious shortcomings of the risk assessment process for determining the safety of nanomaterials. </p>
<p>We have argued that these shortcomings are so significant that risk assessment is effectively a naked emperor.</p>
<h2>Size matters</h2>
<p><a href="https://theconversation.com/au/topics/nanotechnology">Nanotechnology</a> has been heralded as “the next big thing” for more than a decade. It is also <a href="http://nanodb.dk">increasingly found in</a> a variety of products, including paints and surface coatings, sunscreens and cosmetics, clothing and textiles, specialty building products, kitchen appliances and sports equipment. This means they are also increasingly found in our homes, workplaces and environment.</p>
<p>In the nanoscale, familiar substances can <a href="http://sciencelearn.org.nz/Innovation/Innovation-Stories/Revolution-Fibres/Articles/Novel-properties-emerge-at-the-nanoscale">behave differently</a> to their macroscale counterparts. While some of these novel nano properties are potentially useful, the emerging science of <a href="https://en.wikipedia.org/wiki/Nanotoxicology">nanotoxicology</a> also suggests that this novelty can introduce risks to human health and the environment.</p>
<p>This does not mean that all nanomaterials are necessarily dangerous. What it does mean is that we can’t rely on what we know of the same substances in bulk form to provide reliable information about their risks in nano form. </p>
<p>We also can’t rely on the same test methods to investigate their safety. The novel properties of nanomaterials mean that they need dedicated safety testing and risk assessment.</p>
<h2>Reaching for the trigger</h2>
<p>Risk assessment has been the dominant decision-aiding tool used by regulators of new technologies for decades, despite it excluding key questions that the community cares about. For example: do we need this technology; what are the alternatives; how will it affect social relations, and; who should be involved in decision making?</p>
<p>Even on its own terms though, <a href="http://onlinelibrary.wiley.com/doi/10.1111/ropr.12129/abstract">our review</a> found that serious gaps and barriers compromise the risk assessment process when applied to nanomaterials. </p>
<p>A fundamental problem is a lack of nano-specific regulation. Most sector-based regulation does not include a “trigger” for nanomaterials to face specific risk assessment. Where a substance has been approved for use in its macro form, it requires no new assessment. </p>
<p>Even if such a trigger were present, there is also currently no cross-sectoral or international agreement on the definition of what constitutes a nanomaterial.</p>
<p>Another barrier is the lack of measurement capability and validated methods for safety testing. We still do not have the means to conduct routine identification of nanomaterials in the complex “matrix” of finished products or the environment. </p>
<p>This makes supply chain tracking and safety testing under real-world conditions very difficult. Despite ongoing investment in safety research, the lack of validated test methods and different methods yielding diverse results allows scientific uncertainty to persist. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/92512/original/image-20150820-32489-85k25a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/92512/original/image-20150820-32489-85k25a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/92512/original/image-20150820-32489-85k25a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/92512/original/image-20150820-32489-85k25a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/92512/original/image-20150820-32489-85k25a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/92512/original/image-20150820-32489-85k25a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/92512/original/image-20150820-32489-85k25a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/92512/original/image-20150820-32489-85k25a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Carbon nanotubes are one of the substances that have raised nanotoxicology concerns.</span>
<span class="attribution"><span class="source">Geoff Hutchison/Flickr</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>The emperor’s new clothes</h2>
<p>Indeed, scientific uncertainty about nanomaterials’ risk profiles is a <a href="http://www.tandfonline.com/doi/abs/10.3109/17435390.2011.626534#.VbHklKSqpHx">key barrier</a> to their reliable assessment. A <a href="http://www.tandfonline.com/doi/abs/10.3109/10408444.2012.738187#.VbHVZqSqpHw">review</a> funded by the European Commission concluded that:</p>
<blockquote>
<p>[…] there is still insufficient data available to conduct the in depth risk assessments required to inform the regulatory decision making process on the safety of NMs [nanomaterials]. </p>
</blockquote>
<p>Governments also lack information about the extent and location of nanomaterials’ commercial use. In most countries, nano-reporting is not mandatory, and responses to voluntary calls for information have been low. </p>
<p>This leaves both the public and companies in the dark about where nanomaterials are being used. Kris de Meester, the chair of Business Europe’s occupational health and safety committee, has given a personal estimate that <a href="http://www.travailler-mieux.gouv.fr/IMG/pdf/Working_with_nanomaterials_annexI.pdf">99% of European employers are unaware</a> of the presence of nanomaterials in the supply chains for which they have responsibility.</p>
<p>There are also deficiencies in the capacity to manage workplace exposure. There are still relatively <a href="http://www.tandfonline.com/doi/abs/10.3109/17435390.2012.658095#.VbHYqaSqpHw">few nanomaterial-specific Safety Data Sheets</a>, and those that exist generally provide insufficient information or struggle with insufficient instrumentation to manage workplace risks.</p>
<p>Taken together, these barriers mean that the risk assessment is effectively a naked emperor, predicated on capabilities that simply do not exist. </p>
<h2>Exposing the naked emperor</h2>
<p>We suggest that it is time to acknowledge the challenges facing risk assessment of nanomaterials and explore alternative decision-aiding tools that are more publicly accountable. They should incorporate non-risk based questions of social value, and take seriously the need to act in the face of deep uncertainty without the pretension of control. </p>
<p>There are well-developed alternate decision-aiding tools available. One is <a href="http://steps-centre.org/methods/pathways-methods/vignettes/mcm/">multicriteria mapping</a>, which seeks to evaluate various perspectives on an issue. Another is <a href="http://www.ncbi.nlm.nih.gov/pubmed/20122113">problem formulation and options assessment</a>, which expands science-based risk assessment to engage a broader range of individuals and perspectives. </p>
<p>There is also <a href="http://www.gulbenkian.pt/media/files/FTP_files/pdfs/CursoMetodologiasOut08-MathieuCraye&Fern-UM.pdf">pedigree assessment</a>, which explores the framing and choices taking place at each step of an assessment process so as to better understand the ambiguity of scientific inputs into political processes. </p>
<p>Another, though less well developed, approach popular in Europe involves a shift from risk to innovation governance, with emphasis on developing “<a href="https://www.epsrc.ac.uk/research/framework/">responsible research and innovation</a>”.</p>
<p>It is beyond the scope of this article to examine the potential of each of these approaches in depth. Nonetheless, in their explicit attempt to recognise and investigate the implications of scientific uncertainty, and to explore the trade-offs and value judgements implicit in different alternatives, we suggest that such decision-aiding tools would offer more robust bases for nanotechnology regulation than risk assessment.</p><img src="https://counter.theconversation.com/content/44835/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Georgia Miller previously worked for community group Friends of the Earth on nanotechnology issues. She receives an Australian Postgraduate Award in support of her PhD candidature, and has previously received funding from the Australian Nanotechnology Network for an Overseas Travel Fellowship.</span></em></p><p class="fine-print"><em><span>Fern Wickson receives funding for her research from the Research Council of Norway and the European Commission FP7 program.</span></em></p>We need to carefully assess nanomaterials to ensure their safety, but there are questions over whether the existing practice of risk assessment is up to the task.Georgia Miller, PhD candidate, UNSW SydneyFern Wickson, Researcher, GenØk - Centre for BiosafetyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/343452014-11-18T14:36:44Z2014-11-18T14:36:44ZEngineering’s unexpected and microscopic beauty<figure><img src="https://images.theconversation.com/files/64839/original/2yhyrh8h-1416314572.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Asteroidea Electrica, first prize winner by Adrianus Indrat Aria.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/cambridgeuniversity-engineering/14196184589/sizes/l">Cambridge University</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>We all know engineering is useful, functional, even ingenious. But the <a href="http://www.eng.cam.ac.uk/news/art-engineering-images-frontiers-technology">engineering photography competition</a> we hold each year provides us a chance to wander outside its merely utilitarian aspects into dimensions such as beauty, humour and even humanity to find unexpected connections and poetic resonance.</p>
<p>As one of the judges, one quality I look for in the images is some added dimension, a richness, the capacity to trigger a cascade of unrelated ideas. Quite by accident this year a few of the photos shared an unplanned underwater theme.</p>
<p>The winner (above) appeared to be a starfish. There was a column, perhaps from a pier, encrusted with coral and barnacles.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/64841/original/w6w8dhjh-1416314891.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/64841/original/w6w8dhjh-1416314891.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/64841/original/w6w8dhjh-1416314891.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/64841/original/w6w8dhjh-1416314891.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/64841/original/w6w8dhjh-1416314891.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/64841/original/w6w8dhjh-1416314891.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/64841/original/w6w8dhjh-1416314891.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/64841/original/w6w8dhjh-1416314891.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Concrete Crack Bridge for Self-Healing, electron microscopy prize winner, by Tanvir Qureshi.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/cambridgeuniversity-engineering/15627119517/in/set-72157644383738382">Cambridge University</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<p>Then there was a strange ghost fish, the likes of which might range in <a href="http://channel.nationalgeographic.com/videos/the-challenger-deep/">Challenger Deep</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/64840/original/35whvcqq-1416314776.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/64840/original/35whvcqq-1416314776.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/64840/original/35whvcqq-1416314776.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=132&fit=crop&dpr=1 600w, https://images.theconversation.com/files/64840/original/35whvcqq-1416314776.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=132&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/64840/original/35whvcqq-1416314776.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=132&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/64840/original/35whvcqq-1416314776.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=166&fit=crop&dpr=1 754w, https://images.theconversation.com/files/64840/original/35whvcqq-1416314776.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=166&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/64840/original/35whvcqq-1416314776.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=166&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Web of Science I by Christian Hoecker.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/cambridgeuniversity-engineering/14472861836/in/set-72157644383738382/">Cambridge University</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Of course they were none of these things: they were images of carbon nanotubes and graphene, but the forms that emerged at these micro- and nano-scales are familiar from elsewhere in nature. </p>
<p>The winning photo shows a fine pentagonal shape – I lecture on geometry and a question I ask the audience is: “When did you last see a pentagon?” They’re quite rare. They can be found in passionfruit flowers, or the shape of one of the most well-known buildings on the planet. But pentagons in the wild are something of a collector’s item – and this a fine example.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/64842/original/kc6ynqhv-1416315258.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/64842/original/kc6ynqhv-1416315258.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/64842/original/kc6ynqhv-1416315258.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/64842/original/kc6ynqhv-1416315258.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/64842/original/kc6ynqhv-1416315258.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/64842/original/kc6ynqhv-1416315258.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/64842/original/kc6ynqhv-1416315258.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/64842/original/kc6ynqhv-1416315258.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Extrapolated Art II, second prize winner, by Yarin Gal.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/cambridgeuniversity-engineering/14195537938/">Cambridge University</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Second prize went to a re-imagining of a van Gogh painting, as the artist may have painted had he a larger canvas. Based on a playful use of mathematics, a computer algorithm analyses a pattern and style and extrapolates it to fill a larger area. It demonstrates the new <a href="https://www.cs.bris.ac.uk/%7Eflach/mlbook/">science of machine learning</a> that is now entering our lives, from junking spam emails to the product or content recommendations websites suggest.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/64843/original/rszhx4p5-1416315418.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/64843/original/rszhx4p5-1416315418.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/64843/original/rszhx4p5-1416315418.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=405&fit=crop&dpr=1 600w, https://images.theconversation.com/files/64843/original/rszhx4p5-1416315418.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=405&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/64843/original/rszhx4p5-1416315418.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=405&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/64843/original/rszhx4p5-1416315418.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=509&fit=crop&dpr=1 754w, https://images.theconversation.com/files/64843/original/rszhx4p5-1416315418.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=509&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/64843/original/rszhx4p5-1416315418.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=509&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Francis the Engineer, third prize winner, by Anthony Rubinstein-Baylis.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/cambridgeuniversity-engineering/14359051916/in/set-72157644383738382">Cambridge University</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Third prize went to Francis the Engineer, an image that represented the human dimension of engineering. The children’s smiles are fabulous, but emphasise not just happiness but relief at having their essential need for clean drinking water met. Engineering is not all about jet engines, smartphones and nanotubes. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/64844/original/pq4pz9p8-1416315505.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/64844/original/pq4pz9p8-1416315505.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/64844/original/pq4pz9p8-1416315505.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/64844/original/pq4pz9p8-1416315505.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/64844/original/pq4pz9p8-1416315505.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/64844/original/pq4pz9p8-1416315505.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/64844/original/pq4pz9p8-1416315505.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/64844/original/pq4pz9p8-1416315505.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Fractured Rainbows: Mode II Cracks in Glass I, by James Griffith.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/cambridgeuniversity-engineering/14493135381/in/set-72157644383738382">Cambridge University</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>The glass shear pattern is striking, like a flow of lava, or molten sugar, there are hints of rainbows among the sumptuous red – so many positive resonances from what is essentially a piece of broken glass. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/64845/original/y8vfs39m-1416315571.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/64845/original/y8vfs39m-1416315571.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/64845/original/y8vfs39m-1416315571.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/64845/original/y8vfs39m-1416315571.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/64845/original/y8vfs39m-1416315571.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/64845/original/y8vfs39m-1416315571.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/64845/original/y8vfs39m-1416315571.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/64845/original/y8vfs39m-1416315571.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Stretch and Swirl I, by Dhiren Mistry.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/cambridgeuniversity-engineering/14049973155/in/set-72157644383738382/">Cambridge University</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>The similar stretch and swirl image of fluid dynamics reminds me of the timeless pleasure of watching the flicker of bonfire flames, but freeze-framed so you can admire their inner structures: paisley patterns and curling vortices – all this found in what is essentially the inside of an engine chamber.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/64846/original/wr2mdzk8-1416315639.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/64846/original/wr2mdzk8-1416315639.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/64846/original/wr2mdzk8-1416315639.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/64846/original/wr2mdzk8-1416315639.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/64846/original/wr2mdzk8-1416315639.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/64846/original/wr2mdzk8-1416315639.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/64846/original/wr2mdzk8-1416315639.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/64846/original/wr2mdzk8-1416315639.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Carbon Nanotube Clover Field, by Michael De Volder.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/cambridgeuniversity-engineering/14272530138/in/set-72157644383738382">Cambridge University</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>The two images of graphene revealed symmetrical patterns of clover and flowers. The four-leafed clover is a symbol of good fortune, and here there are fields of them, looking like a some architect’s plan of <a href="http://www.dezeen.com/2014/10/02/prentice-womens-hospital-chicago-by-bertrand-goldberg-associates-brutalism/">futuristic tower blocks</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/64847/original/6sq5zfz2-1416315734.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/64847/original/6sq5zfz2-1416315734.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/64847/original/6sq5zfz2-1416315734.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=347&fit=crop&dpr=1 600w, https://images.theconversation.com/files/64847/original/6sq5zfz2-1416315734.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=347&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/64847/original/6sq5zfz2-1416315734.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=347&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/64847/original/6sq5zfz2-1416315734.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=436&fit=crop&dpr=1 754w, https://images.theconversation.com/files/64847/original/6sq5zfz2-1416315734.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=436&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/64847/original/6sq5zfz2-1416315734.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=436&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Graphene Flowers II, by Mari Ijäs.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/cambridgeuniversity-engineering/14046769102/in/set-72157644383738382">Cambridge University</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>The red flowers have six-fold symmetry, and although we rarely give prizes to images created on a computer (it is so much easier to make pretty virtual shapes than to actually build them at the nanoscale) this one pleased with its interconnecting shapes, representing the electrical flow across a graphene lattice.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/64850/original/hkrsdgfs-1416316106.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/64850/original/hkrsdgfs-1416316106.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/64850/original/hkrsdgfs-1416316106.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/64850/original/hkrsdgfs-1416316106.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/64850/original/hkrsdgfs-1416316106.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/64850/original/hkrsdgfs-1416316106.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/64850/original/hkrsdgfs-1416316106.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/64850/original/hkrsdgfs-1416316106.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Natural Engineer in the Field II, by Audrey Hon.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/cambridgeuniversity-engineering/14479281073/in/set-72157644383738382">Cambridge University</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>An old bridge over the River Cam at the back of the engineering department in Cambridge, supported by two truss beams: the photo shows what is known as the “web” of the beam, the vertical face between handrail and deck. And within the web, the photo captures another: the spider’s web shares the same structural principles – the flow of tension within the silk matches that acting on the steel diagonals. I sometimes think that <a href="http://ngm.nationalgeographic.com/2008/04/biomimetics/tom-mueller-text">bio-mimetics</a> is often accompanied by overblown rhetoric, but the unspoken simplicity here appealed to me.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/64848/original/2bsrmzrx-1416315936.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/64848/original/2bsrmzrx-1416315936.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/64848/original/2bsrmzrx-1416315936.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=396&fit=crop&dpr=1 600w, https://images.theconversation.com/files/64848/original/2bsrmzrx-1416315936.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=396&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/64848/original/2bsrmzrx-1416315936.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=396&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/64848/original/2bsrmzrx-1416315936.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=497&fit=crop&dpr=1 754w, https://images.theconversation.com/files/64848/original/2bsrmzrx-1416315936.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=497&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/64848/original/2bsrmzrx-1416315936.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=497&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A contrasting landscape, by Calum Williams, Yunuen Montelongo & Jaime Tenorio-Pearl.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/cambridgeuniversity-engineering/14492583331/in/set-72157644383738382">Cambridge University</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>This nano-scale image is decidedly other-worldly, unlike any landscape I ever saw despite its title. Perhaps it’s where they leave planets to dry before sending them out into the universe. I like how an image of something so small can so readily conjure the impression of something so vast. Perhaps we have the microscope the wrong way round.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/64849/original/y744s4wf-1416316004.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/64849/original/y744s4wf-1416316004.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/64849/original/y744s4wf-1416316004.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=463&fit=crop&dpr=1 600w, https://images.theconversation.com/files/64849/original/y744s4wf-1416316004.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=463&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/64849/original/y744s4wf-1416316004.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=463&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/64849/original/y744s4wf-1416316004.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=582&fit=crop&dpr=1 754w, https://images.theconversation.com/files/64849/original/y744s4wf-1416316004.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=582&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/64849/original/y744s4wf-1416316004.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=582&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Birefringence Earth’s Magnetic Field, by Long Teng.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/cambridgeuniversity-engineering/14226392952/in/set-72157644383738382">Cambridge University</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>The same applies to the magnetic field image: taking aside the extraordinary iridescent colours produced by <a href="http://www.rp-photonics.com/birefringence.html">birefringence</a> (the property of refracting light in different ways), it is an image of something so small as to be almost invisible, yet we see only the Earth itself. I think William Blake <a href="http://www.poetryfoundation.org/poem/172906">said something about that</a> once.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/HsZkLh1BIq4?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
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<p><em>You can see the complete set of photos <a href="https://www.flickr.com/photos/cambridgeuniversity-engineering/sets/72157644383738382/">here</a>.</em></p><img src="https://counter.theconversation.com/content/34345/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Allan McRobie does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>We all know engineering is useful, functional, even ingenious. But the engineering photography competition we hold each year provides us a chance to wander outside its merely utilitarian aspects into dimensions…Allan McRobie, Lecturer in Engineering, University of CambridgeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/107472012-11-15T19:28:51Z2012-11-15T19:28:51ZPower to you: carbon nanotube muscles are going strong<figure><img src="https://images.theconversation.com/files/17653/original/7ds7p7gs-1352949277.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A combination of wax and coiling makes carbon nanotube muscles stronger than ever.</span> <span class="attribution"><span class="source">Science/AAAS</span></span></figcaption></figure><p>Just on a year ago my colleagues and I <a href="https://theconversation.com/show-us-your-carbon-nanotube-artificial-muscles-3821">announced our discovery</a> that <a href="https://theconversation.com/dont-believe-the-hype-carbon-nanotubes-are-merely-extraordinary-321">carbon nanotube</a> yarns could be made to twist and rotate at great speeds when electrically stimulated.</p>
<p>In this way we had created “artificial muscles” that could change their shape in response to stimulus.</p>
<p>The rotating action of these yarns was used to turn a paddle in a microscopic mixer for fluids. Their small size <a href="http://www.youtube.com/watch?v=JQdu8d3EUaY">prompted speculation</a> that these “torsional actuating” threads could one day be used to propel <a href="http://en.wikipedia.org/wiki/Flagellum">flagella-like</a> motors in futuristic micro- or nano-bots.</p>
<p>Over the past year the same team (with some new collaborators) has pushed the performance of these carbon nanotube artificial muscles to staggering new levels.</p>
<p>For a start we’ve been able to increase rotation speeds from 600 revolutions per minute (rpm) to more than 11,000 rpm. The maximum <a href="http://en.wikipedia.org/wiki/Torque">torque</a> (turning force) generated is five-times higher than our previous record and now exceeds the torque generated, per mass, by large electric motors.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/17654/original/5t4yz9wk-1352949277.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/17654/original/5t4yz9wk-1352949277.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=247&fit=crop&dpr=1 600w, https://images.theconversation.com/files/17654/original/5t4yz9wk-1352949277.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=247&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/17654/original/5t4yz9wk-1352949277.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=247&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/17654/original/5t4yz9wk-1352949277.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=311&fit=crop&dpr=1 754w, https://images.theconversation.com/files/17654/original/5t4yz9wk-1352949277.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=311&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/17654/original/5t4yz9wk-1352949277.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=311&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Scanning electron microscope image of a two-ply, carbon nanotube yarn that can be deployed as a torsional muscle in a motor.</span>
<span class="attribution"><span class="source">Science/AAAS</span></span>
</figcaption>
</figure>
<p>Equally exciting is the lengthwise contractions generated in the carbon nanotube yarns. Previously, we measured length contractions of about 1%, but now we can generate up to 9% contractions – similar to natural muscles.</p>
<p>These contractions are also very fast. For 3% contractions we can achieve 1,200 cycles a minute. The mechanical power per weight generated by these contractions is more than 85 times higher than that produced by skeletal muscle.</p>
<p>While these performance improvements are truly impressive, perhaps the most significant advance has been to take the artificial muscle out of the beaker. </p>
<p>Our previous carbon nanotube muscles were powered electrochemically and were configured just like a rechargeable battery with two electrodes (<a href="http://gopsi.ucalegon.com/encyclopedia/cathodesandanodes.html">anode and cathode</a>) immersed in an electrolyte (see video below).</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Qzg2qA1ltK0?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>The carbon nanotube yarns were used for one or both of the electrodes and when charged by applying a voltage, a small increase in yarn volume occurred that resulted in a partial untwisting and shortening of the yarn.</p>
<p>These shape-changes were harnessed for the torsional and contractile muscle actions.</p>
<p>Our new work has focused on other ways of changing yarn volume and the result has been the development of fully dry systems.</p>
<p>The most successful example to date has been to fill up the pore space within the yarns with <a href="http://en.wikipedia.org/wiki/Paraffin">paraffin wax</a> (ordinary candle wax will do) and electrically heat the wax by passing a current through the yarn.</p>
<p>The wax expands and deforms the carbon nanotubes to generate the large and fast rotating or contractile actuations. These new dry actuators no longer need an electrolyte, a second electrode or the associated packaging used to stop electrolyte leakage.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/K0kjj9LctwM?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>An additional bonus is the wax-filled carbon nanotube yarns are much stronger and can be operated for much longer. We gave up testing after 2 million cycles of voltage pulsing where we saw no deterioration in performance.</p>
<p>Even simple exposure to light can be used to heat the paraffin within the carbon nanotube yarn and generate actuation.</p>
<p>Chemically stimulated actuation was also demonstrated by incorporating a guest material within the carbon nanotube yarns that is sensitive to specific chemicals.</p>
<p>When we added <a href="http://en.wikipedia.org/wiki/Palladium">palladium metal</a> to the carbon nanotube yarns we were able to generate reversible torsional actuation with hydrogen gas. Here the metal absorbs hydrogen and swells.</p>
<p>These actuators may be used to automatically close a safety inlet valve when hydrogen pressures exceed a pre-determined threshold.</p>
<p>Similarly, we can imagine “intelligent textiles” where body heat or sunlight cause actuation of yarns within the fabric. Imagine a garment that changes its porosity when the wearer gets hot or sweaty to release heat or moisture and then closes up again when the wearer cools down.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/PdJdy4Y0sjo?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>These applications are genuinely a step closer with the discovery of fully dry actuating yarns. While we have only measured actuation on single yarn threads at present, we are poised to weave, knit and braid these yarns into textile garments and explore their applications in smart textiles. </p>
<p>A curious feature we don’t fully understand is the amplification in actuation that occurs when we over-twist the yarn to form coils.</p>
<p>Over-twisting is easy to demonstrate on any thread or rubber band. Hold one end of the thread firmly and start twisting the other. At first the thread is uniformly twisted but above a threshold level of twist the thread will want to form a coil.</p>
<p>Twist-to-coil transitions can then occur by adjusting the tension on the thread: more tension will pull a coil out and generate more twist.</p>
<p>A non-coiled, twisted carbon nanotube yarn filled with paraffin can generate about 1% contraction in length when heated. Taking the same yarn and adding some extra turns so it becomes coiled will boost the contraction to 5% for the same heat input.</p>
<p>Coiling of threads (or “snarling”) is well known in the textiles industry and even has relevance to the structure and function of DNA.</p>
<p>Understanding the effects of coiling on the actuation of carbon nanotube yarns is part of our ongoing investigations into these fascinating systems.</p><img src="https://counter.theconversation.com/content/10747/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Geoff Spinks receives funding from the Australian Research Council through its Centre of Excellence and Professorial Fellowship grants.</span></em></p>Just on a year ago my colleagues and I announced our discovery that carbon nanotube yarns could be made to twist and rotate at great speeds when electrically stimulated. In this way we had created “artificial…Geoff Spinks, Professor, Intelligent Polymer Research Institute, University of WollongongLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/57432012-03-07T03:21:40Z2012-03-07T03:21:40ZGoing up! The elevator that could take you into space<figure><img src="https://images.theconversation.com/files/8412/original/rq832xz9-1331089396.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A week is a long time to be stuck in a lift.</span> <span class="attribution"><span class="source">MGM</span></span></figcaption></figure><p>A major Japanese construction company, <a href="http://www.obayashi.co.jp/english/">Obayashi Corporation</a>, has <a href="http://www.yomiuri.co.jp/dy/national/T120221004421.htm">announced plans</a> to build a <a href="http://en.wikipedia.org/wiki/Space_elevator">space elevator</a> within 40 years, allowing people to be transported to space stations above the earth.</p>
<p>The proposed design (see below) features a 96,000-kilometre-long cable connecting an earth-based spaceport to <a href="http://upload.wikimedia.org/wikipedia/commons/a/a9/Space_elevator_structural_diagram--corrected_for_scale%2BCM%2Betc.TIF">a counterweight in orbit</a>, roughly a quarter of the way to the moon. An elevator car would then transport people along the cable between the spaceport and a research station 36,000km above the earth – a journey that would take roughly 7.5 days.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/8396/original/hcw3xd8n-1331083286.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/8396/original/hcw3xd8n-1331083286.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/8396/original/hcw3xd8n-1331083286.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=1157&fit=crop&dpr=1 600w, https://images.theconversation.com/files/8396/original/hcw3xd8n-1331083286.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=1157&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/8396/original/hcw3xd8n-1331083286.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1157&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/8396/original/hcw3xd8n-1331083286.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1454&fit=crop&dpr=1 754w, https://images.theconversation.com/files/8396/original/hcw3xd8n-1331083286.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1454&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/8396/original/hcw3xd8n-1331083286.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1454&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption"></span>
<span class="attribution"><span class="source">Obayashi Corp</span></span>
</figcaption>
</figure>
<p>But how realistic a vision is this? And what would a space elevator cable even be made of?</p>
<p>The space elevator concept first entered public consciousness through Arthur C. Clarke’s 1978 science fiction novel <a href="http://en.wikipedia.org/wiki/The_Fountains_of_Paradise">Fountains of Paradise</a>. In the novel, an elevator made of a strong filament or cable was connected to a <a href="http://www.reformation.org/geostationary-satellites.html">geosynchronous satellite</a> to transport materials to and from Earth.</p>
<p>Literary fantasies aside, the reality is that the type of cable proposed by Obayashi Corp. can and will be made. Whether it works or not is another story.</p>
<p>Obayashi Corp’s proposed space elevator will utilise a material discovered in 1991 by Japanese physicist Sumio Iijima – <a href="https://theconversation.com/dont-believe-the-hype-carbon-nanotubes-are-merely-extraordinary-321">carbon nanotubes (CNTs)</a>. CNTs are essentially single tubes (single-walled carbon nanotubes) or multiple concentric tubes (multi-walled carbon nanotubes) comprising sheets of <a href="https://theconversation.com/from-pencil-to-high-speed-internet-graphene-is-a-modern-wonder-3146">graphene</a>. CNTs are one of the strongest materials ever created, stronger than diamond, Kevlar, or even <a href="http://ednieuw.home.xs4all.nl/Spiders/Info/spindraad.htm">spider’s silk</a>.</p>
<p>As such, CNTs would be the ideal material for creating a space elevator cable. Of course there are several issues that need to be addressed before this lofty goal can be realised.</p>
<p>The first, and most fundamental challenge, is that nanotubes can only be grown to <a href="http://www.ncbi.nlm.nih.gov/pubmed/19650638">around 20 centimetres in length</a>, at present. So the first challenge is tethering these tubes together to form ropes, very much like the method used to <a href="http://www.spinningayarn.com.au/">make wool yarn</a>.</p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/8395/original/gp2693vp-1331082990.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/8395/original/gp2693vp-1331082990.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=824&fit=crop&dpr=1 600w, https://images.theconversation.com/files/8395/original/gp2693vp-1331082990.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=824&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/8395/original/gp2693vp-1331082990.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=824&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/8395/original/gp2693vp-1331082990.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1036&fit=crop&dpr=1 754w, https://images.theconversation.com/files/8395/original/gp2693vp-1331082990.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1036&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/8395/original/gp2693vp-1331082990.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1036&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">An artist’s conception of a space elevator climbing through clouds.</span>
<span class="attribution"><span class="source">Liftport</span></span>
</figcaption>
</figure>
<p>CSIRO scientists have started to work on <a href="http://www.csiro.au/files/files/p55a.pdf">making fabrics out of sub-microscopic carbon nanotubes yarns</a>, but the length of the CNTs being used – one to 300 microns, where 1 micron is one-millionth of a metre – make this a real challenge.</p>
<p>Nonetheless the technique of twisting nanotubes into a self-locking yarn has been highly successful. </p>
<p>So while we are close to making reasonably long nanotube yarns there is one intrinsic flaw: the self-locking mechanism in CNT yarns is held together by only <a href="http://www.britannica.com/EBchecked/topic/622645/van-der-Waals-forces">van der Waals interactions</a> – weak intermolecular forces between the nanotubes.</p>
<p>While the accumulation of these interactions along the body of a nanotube makes for quite strong bonding within the yarn, these forces are much weaker than if the tubes were “welded” to one another.</p>
<p>The ideal situation would be to fabricate an individual carbon nanotube 96,000 kilometres long. But this is unlikely: a CNT of this length, when stretched out, could <a href="http://www.lyberty.com/encyc/articles/earth.html">wrap around the earth’s equator more than twice</a> – hardly manageable in a lab.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/8408/original/vpfk5584-1331088660.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/8408/original/vpfk5584-1331088660.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=778&fit=crop&dpr=1 600w, https://images.theconversation.com/files/8408/original/vpfk5584-1331088660.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=778&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/8408/original/vpfk5584-1331088660.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=778&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/8408/original/vpfk5584-1331088660.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=977&fit=crop&dpr=1 754w, https://images.theconversation.com/files/8408/original/vpfk5584-1331088660.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=977&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/8408/original/vpfk5584-1331088660.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=977&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
<span class="attribution"><span class="source">SpaceElevatorGuy</span></span>
</figcaption>
</figure>
<p>Alternatively, scientists could chemically weld (via intramolecular <a href="http://www.chemguide.co.uk/atoms/bonding/covalent.html">covalent bonding</a>) individual nanotubes, preferably end-on-end with a bonding structure similar, if not identical to, the structure of the carbon nanotubes themselves.</p>
<p>Current techniques can easily attach one nanotube to another or <a href="http://www.scientificamerican.com/podcast/episode.cfm?id=new-biosensor-dna-wrapped-carbon-na-08-12-18">attach nanotubes to a variety of other materials</a>, including nanoparticles, DNA, polymers and proteins. These nanocomposites have a broad range of applications from sensors to solar cells.</p>
<p>But in the context of a space elevator cable, the nanotechnologists’ ambition of end-on-end carbon nanotube attachment is still elusive. Achieving this ambition may prove crucial before anyone will feel confident about being lifted into space by elevator.</p>
<p>Clearly without a strong enough material the entire idea of a space elevator is just an intellectual exercise. Happily there is a whole world of scientists out there working hard to turn our dreams into reality.</p><img src="https://counter.theconversation.com/content/5743/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Amanda Ellis receives funding from the Australian Research Council.</span></em></p>A major Japanese construction company, Obayashi Corporation, has announced plans to build a space elevator within 40 years, allowing people to be transported to space stations above the earth. The proposed…Amanda Ellis, Associate Professor of Chemistry/Nanotechnology, Flinders UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/3212011-06-08T00:05:04Z2011-06-08T00:05:04ZDon’t believe the hype: carbon nanotubes are merely extraordinary<figure><img src="https://images.theconversation.com/files/1536/original/aapone-20040702000011917388-usa_space_lift-original_1_.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Tiny but mighty: meet the enduring poster child of the nano-revolution.</span> <span class="attribution"><span class="source">EPA</span></span></figcaption></figure><p>As you read this, researchers around the world are slaving away furiously to develop stronger, smaller and more cost-effective materials for a range of potential uses.</p>
<p>But while there are many “nano-scale” materials in the pipeline, carbon nanotubes (CNTs) remain the “poster child” of the nanotech revolution.</p>
<h2>Science of the (very) small </h2>
<p>Nanotechnology concerns itself with materials that have one or more dimensions in the range of one to 100 <a href="http://searchcio-midmarket.techtarget.com/definition/nanometer">nanometres</a>. To put this in perspective, at the upper limit that’s still 1,000 times thinner than a human hair.</p>
<p>CNTs fall within this range and are made of one or more concentric tubes, or “walls”, of <a href="http://old.iupac.org/goldbook/G02689.pdf">graphitic carbon</a>. They were first introduced to the general and scientific communities by Japanese physicist <a href="http://www.ieeeghn.org/wiki/index.php/Sumio_Iijima">Sumio Iijima</a> in 1991. </p>
<p>But they had been known and understood for at least 40 years prior to that as a tiresome and damaging product formed in the brickwork of furnaces.</p>
<p>If CNTs live up to expectations, their strength and stiffness will make them, weight for weight, several hundred times stronger and stiffer than steel, with the conductivity of copper and thermal properties of diamond. As an added bonus, they will also be cheap to make. </p>
<p>This impressive list of characteristics has made CNTs susceptible to a certain amount of hyping. Visions of super-light airframes and vehicles have emerged, as have stories of paper-thin antiballistic vests and thin, ultra-high-tension powerlines. </p>
<p>Perhaps the most ambitious speculation, complete with <a href="http://science.nasa.gov/science-news/science-at-nasa/2005/27jul_nanotech/">cartoon drawings</a> by NASA, is that CNTs are strong enough to one day build an “elevator” cable into orbit.</p>
<p>We certainly haven’t reached such lofty heights (and may never do so). Maybe as a consequence, those people who bought heavily into the hype around CNTs are now asking what, after two decades of research, has been achieved? Well … </p>
<h2>The good side</h2>
<p>CNTs have fallen in price from thousands of dollars to just a few cents per gram. At the same time, production has risen from grams-per-day to tonnes-per-day, and quality has increased from 99% impurity to 99% CNT. </p>
<p>Easily-achievable lengths have increased from microns to millimetres – a thousand-fold increase – with the longest reported CNT <a href="http://www.ncbi.nlm.nih.gov/pubmed/19650638">now spanning 185 millimetres</a>.</p>
<p>There are now half a dozen technologies for producing pure CNT yarns – including a technology known as “Directly Spinnable Carbon Nanotubes” at CSIRO which can also produce ultra-fine webs and ribbons of short fibre, or “staple” CNTs. </p>
<p>Remarkably, the measured strength and stiffness of individual CNTs has reached between 20% and 80% of the predicted values of (very) approximately <a href="http://bucky-central.me.utexas.edu/RuoffsPDFs/85">100 gigapascals</a> and <a href="http://en.wikipedia.org/wiki/Carbon_nanotube#Strength">one Terapascal</a> respectively. (The variability of these numbers in part reflects the great difficulty in conducting measurements on such tiny objects). Electrical, electronic and thermal properties likewise have largely met predictions.</p>
<p>So what have they been used for? </p>
<p>Well, single nanotubes have been used to make <a href="http://www.physics.berkeley.edu/research/zettl/projects/nanoradio/radio.html">radio transmitters and receivers</a>, atomic balances, sensors and nano-motors. We are also able to disperse and deposit CNTs onto silicon wafers for direct incorporation into semiconductor structures such as transistors.</p>
<h2>The flip side</h2>
<p>The difficulty in achieving nanotube technology’s potential is, at heart, due to CNTs’ current status: simply put, they are neither one thing nor another. CNTs are neither chemicals that can be melted or dissolved and extruded (as we might do with polymers such as Kevlar), nor objects that can be sorted, processed and aligned (as is done with wool fibres). </p>
<p>The dominant force between CNTs is known as the <a href="http://www.damtp.cam.ac.uk/user/gold/pdfs/teaching/van_der_waals.pdf">van der Waals interaction</a>, a ghostly attraction that is insignificant for molecules, because they have so few atoms, and for conventional fibres, because they have so little contact surface area. </p>
<p>For CNTs, with a large number of atoms and a high surface area, the van der Waals interaction is particularly strong.</p>
<p>Our poor understanding and control of this mysterious attraction makes utilisation of the strength of CNTs such a challenge.</p>
<p>With greater knowledge will come the ability to manipulate the interaction and alignment of CNTs, and therefore to build larger and more useful CNT materials.</p>
<p>Immense strides have been taken in the last decade, yet it is still very early days in the nano-revolution both for CNTs and for other materials. </p>
<p>As we move further down the road of discovery we might one day fulfill the world-changing expectations being placed on the shoulders of this technology.</p>
<p>For the moment, though, CNTs are merely extraordinary.</p><img src="https://counter.theconversation.com/content/321/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Stuart Lucas works for CSIRO</span></em></p><p class="fine-print"><em><span>Dr Hawkins works for CSIRO</span></em></p>As you read this, researchers around the world are slaving away furiously to develop stronger, smaller and more cost-effective materials for a range of potential uses. But while there are many “nano-scale…Stuart Lucas, Dr; Research Program Leader: Fibre Science, CSIROStephen Hawkins, Principal Research Scientist, Materials Science and Engineering, CSIROLicensed as Creative Commons – attribution, no derivatives.