Note: This is the first article of a three-part series covering conductive polymer (1) trends, (2) material/process advances and (3) applications.

By way of introduction, the global market for electrically conductive polymers was at $2.2 billion in 2012 and is forecast to grow to $3.4 billion by 2017 for a compound annual growth rate of 6.1 percent. Inherently conductive polymers (ICPs), still considered an "emerging" market, are expected to grow to 23 percent of the electrically conductive polymers market by 2017 for a compound annual growth rate of 16.4 percent versus 5.9 percent for conductive filled plastics.

The ICP market is still small, but it is growing rapidly with hundreds of papers and patents on ICPs published each year. However, the actual record for ICPs has been decidedly mixed. While some have given up on ICPs due to their overall instability and higher prices, many scientists and corporations remain optimistic about eventual significant commercial successes for ICPs.

A number of technical developments are taking place that will improve the performance of ICPs and will — as a result — expand the markets available to these polymers over the next 5-8 years. The most dramatic of these developments relates to nanostructuring conducting polymers in order to provide the advantages associated with higher surface area and better dispersability.

Typical applications for electrically conductive plastics are electrostatic discharge (ESD)/antistatic packaging/electronic housings, electrostatic spray painting and others, including batteries, transistors, light-emitting diodes (LEDs), capacitors, corrosion-resistant coating products, membranes and sensors.

Intensive R&D efforts, early product commercialization, and the high absorption rate of electronic products have made North America the dominant market for conductive polymers with a 65 percent share of the global market, followed by Europe with a 22 percent share.

Next, let's take a look at conductive polymer market growth drivers and challenges. Among conductive polymer product types, filled conductive plastic generates the maximum revenue, contributing approximately 83 percent to the conductive polymer market in 2015, due mainly to its extensive application in ESD and electromagnetic interference (EMI).

Electrically conductive plastic plays an important role in providing low-cost protection against ESD or EMI in miniaturized electronic devices. In addition to rendering the surface of a plastic part less susceptible to the accumulation of electrostatic charges — which attract and hold fine dirt/dust on the surface of the plastic — their use minimizes static discharge that may damage sensitive electronic devices. Because of miniaturization, electronics are increasingly sensitive to particulate contamination and must be protected from lower levels of static charge.

As plastics replace traditional materials like paper and metal, industrial packaging — such as flexible intermediate bulk containers (IBCs) — that must be protected from static discharge is also a growth market for ESD additives. These containers might contain powdered materials such as pharmaceuticals where a spark could lead to fire or dust explosion.

Tek Pak
Four approaches to controlling ESD in plastics sheet (left) and conductive surface resistivity ranges (right).

ATEX, SAEJ1645 and similar safety standards are important drivers. European Union (EU) directive ATEX (Appareils destinés à être utilisés en ATmosphères EXplosibles) affects all new industrial and dynamic devices in hazardous environments where ESD can trigger an explosion of dust or gases. The Society of Automotive Engineerrs (SAE) SAEJ1645 standard targets plastics automotive fuel system components.

Other growth drivers include increasing demand for conductive plastic components used in power cables and electronic packaging. Conductive plastic composites are an important consideration for lightning strike protection in applications such as airliner composite fuselage. These plastics are also finding advanced uses in industrial/consumer electronics, biomedical devices, touch screens/sensors and energy harvesting/storage in response to burgeoning demand for high performance, lightweight inexpensive products.

Further, new carbon nanotube (CNT) production advances by major suppliers have significantly improved supply availability and reduced cost for these key materials. Elsewhere, researchers are advancing CNT technology. For example, a University of Surrey team has discovered a way to grow high-quality CNT over large areas at substrate temperatures below 350 degrees C, making this technology compatible with CMOS (a technology for constructing integrated circuits) and is also suitable for large substrates.

Advances in graphene fabrication methods address what has been a significant obstacle to use of this promising material in high performance electronic devices. The new technique has been used to fabricate an array of 10,000 top-gated transistors on a 0.24 square centimeter chip — one of the most dense graphene devices reported so far.

Finally, let's review technology trends in conductive polymers. While ICPs can serve as conductive additives, they are primarily used in printed electronics, coatings and specialty antistatic compounds such as Stat-Loy from Sabic/LNP.

Compounds of carbon black have excellent price-performance ratios but their adverse effects on mechanical properties are a major drawback. Cabot has developed superconductive carbon black Vulcan Xcmax that overcomes this problem by providing high conductivity at low carbon black loadings.

Dramatically lower CNT loadings are needed to reach a given level of conductivity compared to other conductive fillers is a strong attraction for users wanting to preserve plastic matrix mechanical properties. Compounds such as the "universal" CNT masterbatch from Arkema have been developed to simplify manufacturing operations and avoid issues associated with CNT handling.

CNTs are also considered a viable replacement for indium tin oxide (ITO) transparent conductors in some applications. While the cost of CNT was once prohibitive, it has been coming down in recent years as chemical companies build up manufacturing capacity.

Graphene materials have become commercially available in a short time and are considered a viable candidate in many of the same applications as CNT, including computers, displays, photovoltaics (PV) and flexible electronics. The price and performance advantages of graphene challenge CNT in nanocomposites, coatings, sensors and energy storage applications.

University of Michigan Neural Engineering Lab
Carbon microthread brain prosthetic communication device.

Graphene may supplant the use of CNT and ITO in certain applications. Graphene combined with other flexible transparent electronic components is finding use in OLED (organic LED) and flexible PV cells. Graphene-based transistors are demonstrating high performance and lower cost, thanks to new graphene production methods. Graphene transistors are a potential successor to certain silicon components.

New thermoelectric materials advance energy harvesting possibilities to power miniature electronic devices. Energy harvesters capture small amounts of power for low-energy wireless autonomous electronics such as implantable devices, wireless sensor networks, and wearable electronics.

MXenes, atomically thin, two-dimensional materials similar to graphene promise high-energy storage capabilities. EMI shielding advances in materials and coating applications protect a wide range of electronics from global navigational satellites to children's cochlear implants.

Carbon microthread developments hold hope for brain prosthetic device communication. University of Michigan Neural Engineering Lab researchers have spun an ultrathin electrode from a single carbon fiber that can record neurons in living animals.