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 discovering that a polymer named polyacetylene became conductive when impurities were introduced through a process known as doping.
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.
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.
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 conductive inks.
Plastics
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 Deepwater Horizon explosion in the Gulf of Mexico in 2010 for instance.
Inspired by biological systems, new materials are being 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 first discovery around the turn of the century, many innovative healing systems have been proposed.
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.
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.
These kinds of fibre-reinforced plastics are being increasingly used, particularly in the aerospace industry (the Boeing 787 and the Airbus A360 are 50% composite). Were it not for the high costs, these materials would be used in all vehicles.
More recent additions to the field are nanocomposites, where plastics are instead reinforced with tiny particles of other substances — including graphene. These have any number of potential uses, ranging from lightweight sensors on wind turbine blades to more powerful batteries to internal body scaffolds that speed up the healing process for broken bones.
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.
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.
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 biogas into the major building blocks for manufacturing plastics and synthetic rubbers.
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.
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 discovering that a polymer named polyacetylene became conductive when impurities were introduced through a process known as doping.
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.
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.
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 conductive inks.
