tag:theconversation.com,2011:/au/topics/smart-polymers-14757/articlesSmart polymers – The Conversation2023-06-07T20:07:17Ztag:theconversation.com,2011:article/2065942023-06-07T20:07:17Z2023-06-07T20:07:17ZWe’ve created a new lens that could take thermal cameras out of spy films and put them into your back pocket<figure><img src="https://images.theconversation.com/files/529508/original/file-20230601-25388-svx1ew.jpeg?ixlib=rb-1.1.0&rect=39%2C45%2C4298%2C3205&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>Like something out of a spy movie, thermal cameras make it possible to “see” heat by converting infrared radiation into an image. They can detect infrared light given off by animals, vehicles, electrical equipment and even people – leading to specialised applications in a number of industries.</p>
<p>Despite these applications, thermal imaging technology remains too expensive to be used in many consumer products such as self-driving cars or smartphones. </p>
<p>Our team at Flinders University has been working hard to turn this technology into something we can all use, and not just something we see in spy movies. We’ve developed a low-cost thermal imaging lens that could be scaled up and brought into the lives of everyday people. Our findings <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/adom.202300058">are published</a> in the journal Advanced Optical Materials. </p>
<h2>Thermal imaging across industries</h2>
<p>Thermal imaging has obvious applications in surveillance and security, given its ability to detect the heat signature of people. It’s not surprising defence forces all over the world use this technology – <a href="https://www.dst.defence.gov.au/innovation/heat-imaging-technology-infrared">including in Australia</a>. </p>
<p>In medicine, it can be used to detect tissues of a higher temperature. This means thermal cameras are useful in the <a href="https://www.hindawi.com/journals/misy/2022/8952849/#abstract">non-invasive detection</a> of tumours, which run at a higher metabolism (and temperature) than healthy tissue. </p>
<p>Thermal imaging even plays a crucial role in <a href="https://spinoff.nasa.gov/spinoff1997/ps2.html">space exploration</a>. For instance, it can be used to image distant stars, galaxies and planets, because infrared light can penetrate dust clouds much better than visible light. NASA’s James Webb Space Telescope <a href="https://www.nasa.gov/image-feature/goddard/2022/nasa-s-webb-delivers-deepest-infrared-image-of-universe-yet">also takes</a> infrared images – and its ability to see far “redder” wavelengths is opening up new corners of the universe for us.</p>
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<a href="https://theconversation.com/two-experts-break-down-the-james-webb-space-telescopes-first-images-and-explain-what-weve-already-learnt-186738">Two experts break down the James Webb Space Telescope's first images, and explain what we've already learnt</a>
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<h2>Addressing the high-cost conundrum</h2>
<p>Above are just some examples in a long list of the specialised applications of thermal imaging. Yet this technology could have many more potential uses if it wasn’t so expensive to produce.</p>
<p>The high cost comes, in part, from the materials used to produce the camera lenses. These lenses need to have special properties that allow them to be used with infrared radiation in a way standard lenses can’t.</p>
<p>Most glasses and plastics will absorb infrared radiation, so expensive materials such as germanium or zinc selenide must be used. Both materials can be difficult to manufacture and maintain; <a href="https://www.usgs.gov/data/germanium-deposits-united-states#:%7E:text=Germanium%2C%20which%20is%20currently%20classified,Alaska%2C%20Washington%2C%20and%20Tennessee">germanium</a> is a critical element in short supply, and zinc selenide <a href="https://www.ncbi.nlm.nih.gov/books/NBK216723/">contains toxic elements</a>.</p>
<p>Our team wanted to address the lens challenge head-on. We developed a new polymer made from the low-cost and abundant building blocks of sulfur and cyclopentadiene (an organic compound that takes the form of a colourless liquid). </p>
<p>The cost of the raw materials for the lens we’ve developed is less than one cent per lens. In comparison, some germanium lenses can <a href="https://www.edmundoptics.com.au/search/?criteria=Germanium%20lenses&Tab=Products#ProductFamilies_ii=ProductFamilies_ii%3AMTQxODA1">cost thousands of dollars</a>.</p>
<p>This new sulfur-based lens can also be moulded and cast into a variety of complex shapes through common techniques used in the plastics industry. These techniques are simpler and less energy-intensive than those used to create conventional infrared lenses – further reducing the cost and making the polymer more scalable.</p>
<p>The key to developing this material was figuring out how to use cyclopentadiene as a gas for the reaction with sulfur. By doing this, we could precisely control the composition of the resulting polymer – leading to a lens with enhanced capabilities for thermal imaging.</p>
<p>Despite being completely opaque to visible light, the polymer has the highest long-wave infrared transmission of any plastic that has been reported – which means it can be used with a thermal imaging camera.</p>
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<span class="caption">The lens is black and opaque.</span>
<span class="attribution"><span class="license">Author provided</span></span>
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<h2>Possible applications</h2>
<p>The development of this material opens doors to many new thermal imaging applications that weren’t possible before.</p>
<p>Self-driving cars could use this technology to detect pedestrians or vehicles – even in low light or fog. Or it could be used in agriculture to monitor irrigation and crop health. Importantly, it would be affordable for farmers. </p>
<p>The new lens is also lightweight, which is helpful for aerial imaging by drone. </p>
<p>Finally, it could be integrated into consumer electronics such as smartphones, computers and home automation systems, to name a few. This would enable users to take thermal images or videos at any time from their phone. It could even be used to create next-generation smoke alarms.</p>
<p>The advances developed in this new study have significantly reduced the barrier to using thermal imaging – and may help revolutionise how it’s used in our everyday lives.</p>
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Read more:
<a href="https://theconversation.com/weve-created-a-device-that-could-allow-instant-disease-diagnosis-while-fitting-inside-your-phone-lens-181342">We've created a device that could allow instant disease diagnosis – while fitting inside your phone lens</a>
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<p class="fine-print"><em><span>Samuel Tonkin studies at Flinders University. He receives funding from Flinders University Impact Seed Funding for Early Career Researchers and the Australian Research Council (DP200100090 and FT220100054) awarded to Future Fellow Prof Justin Chalker. Additional support for quantum mechanical calculations was also provided by the ARC to Prof Michelle Coote (DP210100025). Samuel Tonkin is an inventor on a provisional patent application covering the manufacture and use of thermal imaging materials discussed in this article (AU2022900289).</span></em></p><p class="fine-print"><em><span>Justin M. Chalker receives funding from Flinders University and the Australian Research Council (FT220100054, DP230100587, DP200100090) for this project. Justin Chalker is an inventor on a provisional patent application covering the manufacture and use of the thermal imaging materials discussed in this article (AU2022900289). </span></em></p>The costs of the materials is less than one cent per lens.Samuel Tonkin, PhD Candidate, College of Science and Engineering, Flinders UniversityJustin M. Chalker, Matthew Flinders Professor of Chemistry, Flinders UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/747282017-03-22T18:33:37Z2017-03-22T18:33:37Z3-D printing turns nanomachines into life-size workers<figure><img src="https://images.theconversation.com/files/162085/original/image-20170322-12437-jb8bq0.jpg?ixlib=rb-1.1.0&rect=125%2C107%2C3628%2C2005&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Molecular machines are ready to join forces and take on real-world work.</span> <span class="attribution"><span class="source">Chenfeng Ke</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Nanomachines are tiny molecules – more than 10,000 lined up side by side would be narrower than the diameter of a human hair – that can move when they receive an external stimulus. They can already <a href="http://www.pnas.org/content/102/29/10029">deliver medication</a> within a body and serve as <a href="http://www.nature.com/nature/journal/v445/n7126/full/nature05462.html">computer memories</a> at the microscopic level. But as machines go, they haven’t been able to do much physical work – until now. </p>
<p><a href="http://www.keresearchgroup.com">My lab</a> has used nano-sized building blocks to <a href="http://onlinelibrary.wiley.com/doi/10.1002/anie.201612440/full">design a smart material</a> that can perform work at a macroscopic scale, visible to the eye. A 3-D-printed lattice cube made out of polymer can lift 15 times its own weight – the equivalent of a human being lifting a car.</p>
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<figcaption><span class="caption">Our polymer is able to lift an aluminum plate when chemical energy is added in the form of a solvent.</span></figcaption>
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<h2>Nobel-winning roots are rotaxanes</h2>
<p>The design of our new material is based on <a href="https://www.nobelprize.org/nobel_prizes/chemistry/laureates/2016/">Nobel Prize-winning research</a> that turned mechanically interlocked molecules into work-performing machines at nanoscale – things like <a href="http://doi.org/10.1126/science.1094791">molecular elevators</a> and <a href="http://doi.org/10.1038/nature10587">nanocars</a>.</p>
<p>Rotaxanes are one of the most widely investigated of these molecules. These dumbbell-shaped molecules are capable of converting input energy – in the forms of light, heat or altered pH – into molecular movements. That’s how these kinds of molecular structures got the nickname “<a href="https://www.nobelprize.org/nobel_prizes/chemistry/laureates/2016/popular-chemistryprize2016.pdf">nanomachines</a>.”</p>
<p>For example, in a molecule called [2]rotaxane, composed of one ring on an axle, the ring can move along the axle to perform shuttling motions. </p>
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<span class="caption">Left, a [2]rotaxane. The ring can shuttle along the axle. Right, representation of billions of [2]rotaxanes in solution. The motions of nano-rings counteract macroscopically.</span>
<span class="attribution"><span class="source">Chenfeng Ke</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p>So far, harnessing the mechanical work of rotaxanes has been very challenging. When billions of these tiny machines are randomly oriented, the ring motions will cancel each other out, producing no useful work at a macroscale. In order to harness these molecular motions, scientists have to think about controlling their three-dimensional arrangement as well as synchronizing their motions. </p>
<h2>Molecular beads on a string</h2>
<p>Our design is based on a well-investigated family of molecules called polyrotaxanes. These have multiple rings on a molecular axle. In our new material, the ring is a cyclic sugar and the axle is a polymer. </p>
<p>If we provide an external stimulus – like adding water – these rings randomly shuttling back and forth can instead stick to each other and form a tubular array. When that happens, it changes the stiffness of the molecule. It’s like when beads are threaded onto a string; many beads slid together make the string much stronger, like a rod.</p>
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<span class="caption">Cartoon presentation of a polyrotaxane. The rings are changed from the shuttling state, left, to the stationary state, right.</span>
<span class="attribution"><span class="source">Chenfeng Ke</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p>Our approach is to build a polymer system where billions of these molecules become stronger with added water. The strength of the whole architecture is increased and the structure can perform useful work.</p>
<p>In this way, we were able to get around the original problem of the random orientation of many nanomachines together. The addition of water locks them into a stationary state, therefore strengthening the whole 3-D architecture and allowing the united molecules to perform work together. </p>
<h2>3-D printing the material</h2>
<p>Our research is the first to add 3-D printability to mechanically interlocked molecules. It was integrating the 3-D printing technique that allowed us to transform the random shuttling motions of nano-sized rings into smart materials that perform work at macroscopic scale.</p>
<p>Getting the molecules all lined up in the right orientation is a way to amplify their motions. When we add water, the rings of the polyrotaxanes stick together via hydrogen bonds. The tubular arrays then stack together in a more ordered manner.</p>
<p>It’s much easier to get the molecules coordinated while they’re in this configuration as opposed to when the rings are all freely moving along the axle. We were able to successfully print lattice-like 3-D structures with the rings locked into position in this way. Now the molecules aren’t just randomly positioned within the material.</p>
<p>After 3-D-printing out the polymer, we used a photo-curing process – similar to the UV lamp that hardens nail polish at a salon – to cure it. We were left with a material that had good 3-D structural integrity and mechanical stability. Now it was ready to do some work.</p>
<h2>Shape changing back and forth</h2>
<p>The three-dimensional geometry of the polymer is crucial for its shape changing. A hollow structure is easier to deform than a solid one. So we designed a lattice cube structure to maximize its shape-deformation ability and, in turn, its ability to do work as it switched back and forth from one state to the other.</p>
<p>The next important step was being able to control the work our polymer could do.</p>
<p>It turns out the complex 3-D architecture of these structures can be reversibly deformed and reformed. We were able to use a solvent to switch the threaded ring structure between random shuttling and stationary states at the molecular level. Exchanging the solvent let us easily repeat this shape-changing and recovery behavior many times.</p>
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<figcaption><span class="caption">Squirting in solvent adds chemical energy to our polymer. As the solvent evaporated over time, the polyrotaxane returned to its original form.</span></figcaption>
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<p>This is how we converted chemical energy into mechanical work.</p>
<p>Just like moving beads to strengthen or weaken a string, this shape-changing is critical because it allows the amplification of molecular motion into macroscopic motion.</p>
<p>A 3-D printed lattice cube made of this smart material lifted a small coin 1.6 millimeters. The numbers may sound small for our day-to-day world, but this is a big step forward in the effort to get nanomachines doing macro work.</p>
<p>We hope <a href="http://onlinelibrary.wiley.com/doi/10.1002/anie.201612440/full">this advance</a> will enable scientists to further develop smart materials and devices. For example, by adding contraction and twisting to the rising motion, molecular machines could be used as soft robots performing complicated tasks similar to what a human hand can do.</p><img src="https://counter.theconversation.com/content/74728/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Chenfeng Ke does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Research on molecular machines won last year’s Nobel Prize in chemistry. Now scientists have figured out a way to get these tiny molecules to join forces and collaborate on real work on a macro scale.Chenfeng Ke, Assistant Professor of Chemistry, Dartmouth CollegeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/666222016-10-06T16:54:53Z2016-10-06T16:54:53ZShape-shifting materials could be crucial in tight spaces – such as inside our bodies<figure><img src="https://images.theconversation.com/files/140738/original/image-20161006-14726-1uj9lcb.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">cybrain/shutterstock.com</span></span></figcaption></figure><p>The rise of 3D printing means it’s now easy to create objects to any design we like from scratch, something that’s already finding particular use in medicine, with 3D printed <a href="http://3dprint.nih.gov/collections/prosthetics">customised prosthetics</a> or even <a href="http://www.bbc.co.uk/news/uk-england-hampshire-27436039">replacement bones such as hip joints</a>. Going one step further is to create so-called “<a href="https://theconversation.com/explainer-what-is-4d-printing-35696">4D printed materials</a>” that once created can change their shape.</p>
<p>Following decades of research by chemists, engineers, physicists and biologists this promising field of “smart materials” includes polymer-based (plastic) materials that can drastically change their properties if <a href="http://www.nature.com/nmat/journal/v9/n2/abs/nmat2614.html">triggered by changing environmental factors</a> such as heat, moisture or pH. Now, in a recently published paper, US researchers have demonstrated novel smart materials that can be pre-programmed to shape-shift in specific ways, without the need for an external stimulus to trigger the change.</p>
<p>Smart polymers have been put to many uses. For example, as nanoparticles that only form when a <a href="http://pubs.rsc.org/en/Content/ArticleLanding/2014/CC/c4cc04139a#!divAbstract">solution is shaken</a>, or dissolve to release a pharmaceutical when the nanoparticle is taken up by a <a href="http://pubs.acs.org/doi/abs/10.1021/acs.chemrev.5b00346">living cell</a>. Or nanoparticles that shape-shift into a different type of nanoparticle when the temperature changes, and <a href="http://pubs.acs.org/doi/abs/10.1021/ja3024059">shape-shift back again</a> when the temperature change is reversed. On a much larger scale, smart materials have been used to create <a href="https://application.wiley-vch.de/books/sample/3527318291_c01.pdf">self-healing systems</a>, where the mechanical forces that cause breakages also initialise chemical reactions that glue two broken pieces back together. </p>
<p>What all these smart materials have in common is that they only react to external stimulation. Being able to “program” smart materials to shape-shift without a trigger, as demonstrated in the new paper, is a new achievement.</p>
<h2>Pitting physical against chemical</h2>
<p>Published in Nature Communications, the <a href="http://www.nature.com/articles/ncomms12919">study</a> focuses on the preparation of cylinder-shaped polymer hydrogels: soft pieces of plastic that contain water, similar to the material soft contact lenses are made from. </p>
<p>The usual mechanical behaviour of these plastic cylinders relies on its chemical structure, made up of two sets of bonds between individual chains of polymers. The first type of bonds that hold the cylinder material together are known as chemical crosslinks, which are permanent and do normally not break. The second are the many physical hydrogen bonds that hold the plastic cylinder together. Crucially, while initially stable, these hydrogen bonds can be broken under sufficient stress, becoming soft and then reforming in a different configuration.</p>
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<figcaption>
<span class="caption">Diagram showing how polymer chains (top) break and reform in new shapes as time progresses (bottom).</span>
<span class="attribution"><a class="source" href="http://www.naure.com/articles/ncomms12919#f1">Xiaobo Hu et al/Nature</a></span>
</figcaption>
</figure>
<p>Left for enough time – perhaps days – this material will eventually assume the shape in which the strong chemical crosslinks are least strained. This is just the same as how a rubber band returns to its original resting shape after having been stretched (only a rubber band moves much faster). </p>
<p>In the study, the researchers forced one of their smart material cylinders into a specific shape for a period of time. While deformed, the material’s chemical structure attempts to reform into its original shape, just as a rubber band does. However, depending on how long the cylinder is bent out of shape, the physical hydrogen bonds inside the material will break and reform in a way that actually favours the new, bent, shape. </p>
<p>When released, an internal struggle begins inside the cylinder during which its chemical structure attempts to revert to its original shape, but to do so requires the physical network of hydrogen bonds to revert to its original form, which can take some time.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/140711/original/image-20161006-14719-ihf11k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/140711/original/image-20161006-14719-ihf11k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/140711/original/image-20161006-14719-ihf11k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=308&fit=crop&dpr=1 600w, https://images.theconversation.com/files/140711/original/image-20161006-14719-ihf11k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=308&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/140711/original/image-20161006-14719-ihf11k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=308&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/140711/original/image-20161006-14719-ihf11k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=387&fit=crop&dpr=1 754w, https://images.theconversation.com/files/140711/original/image-20161006-14719-ihf11k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=387&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/140711/original/image-20161006-14719-ihf11k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=387&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Rose petals made from shape-shifting materials, programmed to open one after the other, with the bud opening into a flower.</span>
<span class="attribution"><a class="source" href="http://www.nature.com/articles/ncomms12919#f4">Xiaobo Hu et al/Nature</a></span>
</figcaption>
</figure>
<h2>Timing is crucial</h2>
<p>The authors demonstrated that the time the material requires to revert to its original shape depends on how long it is held bent out of shape. The longer it spends deformed, the more the physical connections become accustomed to the new change and the longer it takes for the cylinder to relax back. </p>
<p>Impressively, this means the researchers were able to show that one of their smart material cylinders could be programmed to perform a specific routine by applying several bends, each held for different lengths of time. They were also able to program a time lag, applying a thin water-soluble coating to the cylinder which prevents the cylinder from starting its shape-shifting until the coating becomes soft from immersion in water.</p>
<p>Given the large and growing interest in smart materials, this research offers an interesting new approach to their design and manipulation. Adding the element of timing and trigger-free activation into the design of smart materials offers all sorts of uses, for example home products that adapt to heat or moisture. And of course there’s enormous potential for biomedical treatments, such as minimally invasive surgical procedures, autonomous actuators, slow-release methods for drugs, or physical implants that respond to environmental changes, even within the body.</p><img src="https://counter.theconversation.com/content/66622/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Peter Roth 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>Programmable materials that can change shape could have all manner of potential uses.Peter Roth, Lecturer in Applied Organic Chemistry, University of SurreyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/371312015-02-04T06:01:36Z2015-02-04T06:01:36ZFive synthetic materials with the power to change the world<figure><img src="https://images.theconversation.com/files/70963/original/image-20150203-25551-14x69r9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Inside Boeing's Dreamliner: tomorrow's polymers today</span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/cat.mhtml?lang=en&language=en&ref_site=photo&search_source=search_form&version=llv1&anyorall=all&safesearch=1&use_local_boost=1&search_tracking_id=psoLMPJil8aZQIbiihuHMA&searchterm=dreamliner&show_color_wheel=1&orient=&commercial_ok=&media_type=images&search_cat=&searchtermx=&photographer_name=&people_gender=&people_age=&people_ethnicity=&people_number=&color=&page=1&inline=177184352">Jordan Tan</a></span></figcaption></figure><p>The New York <a href="http://www.theatlantic.com/photo/2013/11/the-1939-new-york-worlds-fair/100620/">World’s Fair of 1939-40</a> was one of the greatest expos the world had ever seen. Visitors to Flushing Meadow Park in Queens were invited to see the “world of tomorrow” giving them a first glimpse of wonders such as the television, the videophone and the Ford Mustang. </p>
<p>It was also the first chance to see nylon, the world’s first fully synthetic man-made fibre. It was being sewn into pantyhose by a display of knitting machines as two models played tug of war to demonstrate the strength of the fabric. Nylon had been discovered by the <a href="http://www.acs.org/content/acs/en/education/whatischemistry/landmarks/carotherspolymers.html">Wallace Carothers’</a> group in DuPont’s research division four years earlier. It was introduced at the fair as the new hosiery “wholly fabricated from such common raw materials as coal, water and air” which could be made into filaments “as strong as steel”.</p>
<p>Nylon stockings went on <a href="http://inventors.about.com/od/nstartinventions/a/Nylon_Stockings.htm">to become</a> a huge success, of course, selling 64m pairs for DuPont in their first year alone. Nylon had qualities that were superior to those of the natural product, silk, and it soon found many useful, if sometimes less fashionable, applications. Today it is still used very widely in fabrics, upholstery, sport articles, instrument strings and automotive parts. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/70959/original/image-20150203-25536-282j01.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/70959/original/image-20150203-25536-282j01.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/70959/original/image-20150203-25536-282j01.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/70959/original/image-20150203-25536-282j01.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/70959/original/image-20150203-25536-282j01.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/70959/original/image-20150203-25536-282j01.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/70959/original/image-20150203-25536-282j01.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/70959/original/image-20150203-25536-282j01.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>
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<span class="caption">Nylon: left the shelves like iPhones on steroids.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/cat.mhtml?lang=en&language=en&ref_site=photo&search_source=search_form&version=llv1&anyorall=all&safesearch=1&use_local_boost=1&searchterm=nylon%20stocking&show_color_wheel=1&orient=&commercial_ok=&media_type=images&search_cat=&searchtermx=&photographer_name=&people_gender=&people_age=&people_ethnicity=&people_number=&color=&page=1&inline=3114302">Rebecca Abell</a></span>
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<p>Since the dawning of this new era of fully synthetic materials, the advances have been unparallelled in the history of materials. Chemists have discovered new catalysts and developed new synthetic routes to join small molecules into long polymer chains with the right properties for a particular use – the <a href="http://www.victoriacarpets.com/carpet-type.aspx?id=4">polypropylene fibres</a> that we use in carpets for example, or hard varieties of <a href="http://www.medicinenet.com/plastic/page2.htm">polyethylene</a> for making plastic bottles. </p>
<p>Physicists, materials scientists and engineers have also designed new processing methods and new technologies to enhance performance to create substances like super-tough substances like <a href="http://www.explainthatstuff.com/kevlar.html">kevlar</a>. </p>
<p>Quite rightly, we are becoming more demanding at the same time. We expect products that will further enhance the quality of our lives, but we want materials and technologies that are increasingly energy efficient, sustainable and capable of reducing global pollution. It’s a challenge.</p>
<p>Here are five types of polymers that will shape the future.</p>
<h2>1. Bioplastics</h2>
<p>As we are often reminded, plastics do not degrade and are a very visible source of environmental pollution. To complicate things further, the building blocks of these materials, which we call monomers, are historically derived from crude oil, which is not renewable. </p>
<p>But this is changing. Thanks to innovations with the processes for using enzymes and catalysts, it is becoming increasingly possible to convert renewable resources such as <a href="http://www.biogas-info.co.uk/">biogas</a> into the major building blocks for manufacturing plastics and <a href="http://www.britannica.com/EBchecked/topic/182081/elastomer">synthetic rubbers</a>. </p>
<p>These substances are sustainable because they save fossil resources. But of course this only partly solves the problem. Unless they are also biodegradable, they are still a problem for the environment. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/70961/original/image-20150203-25554-1q7y1ff.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/70961/original/image-20150203-25554-1q7y1ff.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/70961/original/image-20150203-25554-1q7y1ff.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=421&fit=crop&dpr=1 600w, https://images.theconversation.com/files/70961/original/image-20150203-25554-1q7y1ff.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=421&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/70961/original/image-20150203-25554-1q7y1ff.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=421&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/70961/original/image-20150203-25554-1q7y1ff.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=529&fit=crop&dpr=1 754w, https://images.theconversation.com/files/70961/original/image-20150203-25554-1q7y1ff.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=529&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/70961/original/image-20150203-25554-1q7y1ff.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=529&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Plastic cups that grow on trees!</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/cat.mhtml?lang=en&language=en&ref_site=photo&search_source=search_form&version=llv1&anyorall=all&safesearch=1&use_local_boost=1&searchterm=nylon%20stocking&show_color_wheel=1&orient=&commercial_ok=&media_type=images&search_cat=&searchtermx=&photographer_name=&people_gender=&people_age=&people_ethnicity=&people_number=&color=&page=1&inline=3114302">photokup</a></span>
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<h2>2. Plastic composites/nanocomposites</h2>
<p>Plastic composites are the name for plastics which have been reinforced by different fibres to make them stronger or more elastic. For example you can make a polymer stronger by embedding carbon fibres, which creates a lightweight material which is ideal for modern fuel-efficient transport. </p>
<p>These kinds of fibre-reinforced plastics are being increasingly used, particularly in the aerospace industry (the <a href="http://www.boeing.com/boeing/commercial/787family/programfacts.page">Boeing 787</a> and the <a href="http://www.airbus.com/aircraftfamilies/passengeraircraft/a350xwbfamily/technology-and-innovation/">Airbus A360</a> are 50% composite). Were it not for the high costs, these materials would be used in all vehicles.</p>
<p>More recent additions to the field are nanocomposites, where plastics are instead reinforced with tiny particles of other substances – including <a href="https://www.youtube.com/watch?v=AsmqOOWJL24">graphene</a>. These have any number of potential uses, <a href="http://www.understandingnano.com/nanocomposites-applications.html">ranging from</a> lightweight sensors on wind turbine blades to more powerful batteries to internal body scaffolds that speed up the healing process for broken bones. </p>
<p>Nanocomposites will become particularly exciting if we succeed in producing them through processing methods that make it possible to design them in a very controlled manner. If we look at the structures of materials in nature, such as wood, you find they are incredibly complicated and intricate. Our current composites and nanocomposites are very unsophisticated by comparison. </p>
<h2>3. Self-healing polymers</h2>
<p>No matter how carefully we select materials for engineering applications based on their ability to withstand mechanical stresses and environmental conditions, they will inevitably fail. Ageing, degradation and loss of mechanical integrity due to impact or fatigue are all contributing factors. Not only is this very costly, it can be disastrous, as was the case with the <a href="http://www.bp.com/en/global/corporate/gulf-of-mexico-restoration/deepwater-horizon-accident-and-response.html">Deepwater Horizon explosion</a> in the Gulf of Mexico in 2010 for instance.</p>
<p>Inspired by biological systems, new materials <a href="http://www.rsc.org/chemistryworld/2014/05/polymer-sets-new-self-healing-record">are being</a> developed which are able to heal in response to what would be traditionally considered irreversible damage. Polymers are not the only materials with the potential for self-healing, but they seem to be very good at it. Within a few years since their <a href="http://www.explainthatstuff.com/self-healing-materials.html">first discovery</a> around the turn of the century, many innovative healing systems have been proposed. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/1i3yoK0C9Ag?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
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<p>What is still incredibly challenging is the idea of extending these concepts to large-volume applications, since self-healing polymers demand much more complicated design than previous generations of polymers. But this seems the ultimate route towards long-lasting, fault-tolerant materials that can be used for products including coatings, electronics and transport.</p>
<h2>4. Plastic electronics</h2>
<p>Most polymers are insulators and therefore don’t conduct electricity. However an upsurge in this field of polymer research emerged in 2000 after the award of a Nobel Prize to Alan MacDiarmid, Alan Heeger and Hideki Shirakawa for work on <a href="http://www.org-chem.org/yuuki/shirakawa/shirakawa_en.html">discovering that</a> a polymer named polyacetylene became conductive when impurities <a href="http://www.nobelprize.org/nobel_prizes/chemistry/laureates/2000/advanced-chemistryprize2000.pdf">were introduced</a> through a process known as doping. </p>
<p>Not only does the same process make other similar polymers conductive, some can even be converted into light-emitting diodes (LEDs), raising the prospect of flexible computer screens like the one below. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/70967/original/image-20150203-25551-jiolyp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/70967/original/image-20150203-25551-jiolyp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/70967/original/image-20150203-25551-jiolyp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=586&fit=crop&dpr=1 600w, https://images.theconversation.com/files/70967/original/image-20150203-25551-jiolyp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=586&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/70967/original/image-20150203-25551-jiolyp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=586&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/70967/original/image-20150203-25551-jiolyp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=736&fit=crop&dpr=1 754w, https://images.theconversation.com/files/70967/original/image-20150203-25551-jiolyp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=736&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/70967/original/image-20150203-25551-jiolyp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=736&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Flexible screen display by Plastic Logic.</span>
<span class="attribution"><a class="source" href="http://en.wikipedia.org/wiki/Plastic_Logic#mediaviewer/File:Flexed_plastic_display.jpg">Plastic Logic</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
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<p>This is an area where polymers still face considerable challenge and strong competition from incumbents like silicon and organic LEDs. Still, when looking for cheap flexible replacements to existing electronic devices, polymers have much to offer as they can be easily processed in solutions and can be 3D-printed. </p>
<p>There seems to be enormous research going on in this area, with polymers sometimes playing the role of the active component, such as in semiconductors, and sometimes acting as a vehicle for other substances, such as in <a href="http://www.henkel-adhesives.com/conductive-inks-coatings-27433.htm">conductive inks</a>. </p>
<h2>5. Smart and reactive polymers</h2>
<p>Gels and synthetic rubbers can easily adjust their shape in response to external stimuli, which means they are able to respond to changes in their surroundings. The external stimulus would usually be a change in temperature or acidity/alkalinity but it could equally be light, ultrasound or chemical agents. This turns out to be incredibly useful in designing smart materials for sensors, drug delivery devices and many other applications. </p>
<p>You can greatly extend a polymer’s natural ability to respond to such stimuli by designing them with this purpose in mind. Mechanophores, for example, are molecular units that can alter the properties of a polymer when they are subjected to mechanical forces. These could have any number of industrial applications, especially if self-healing technology was incorporated too. </p>
<p>Other possibilities for smart polymers include things like window coatings that can wash the windows when they are dirty, and medical stitches that disappear when an injury has healed. </p>
<figure>
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</figure><img src="https://counter.theconversation.com/content/37131/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Valeria Arrighi 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>The New York World’s Fair of 1939-40 was one of the greatest expos the world had ever seen. Visitors to Flushing Meadow Park in Queens were invited to see the “world of tomorrow” giving them a first glimpse…Valeria Arrighi, Associate professor, Heriot-Watt UniversityLicensed as Creative Commons – attribution, no derivatives.