Where Inks & Coatings Intersect, Pt.II

Today, opportunities in the electromagnetic compatibility (EMC) industry are constrained by what is possible based on cost and regulatory requirements.
   
As many electronic devices use less metal in their enclosures in order to reduce costs, the requirements for EMC increase since a potential Faraday cage—a conductive enclosure completely surrounding the shielded object—is lost.
   
Electromagnetic interference (EMI) is highly regulated by government agencies throughout the world. Thus aside from the actual performance of the devices and their impact on, and from, other devices, additional EMC requirements may be present because of the regulations. While the goals are similar in the various geographies around the globe, there are differences that can impact the EMC approaches used in manufacturing for different target geographies.
   
As a result, materials firms have long been on the lookout for new materials that can generate profits for them in the EMC sector. Materials that have been tested or used in this sector include conductive polymers, TCOs and carbon materials.
   
Carbon nanotubes can be used for EMC applications in small quantities and are not inherently expensive. Their current high cost is due to their newness. Carbon nanotubes, or some of them anyway, are more conductive than any metal and are easily made into diffusely dispersed suspensions. Carbon nanotube coatings or filled polymers can offer an interpenetrating conductive network that produces a Faraday cage with minimal quantities of material.
   
Conductive polymers like PEDOT:PSS have proved suitable for some EMC applications. However, they have not come down in price as rapidly as hoped. Still, they are flexible and often transparent, especially in thin layers, and offer the likelihood of low cost within the next several years. All of these features are attractive in certain EMC applications.
   
Other nanomaterials used for EMC coatings include metals, mostly silver. The small size of nanoparticles offers the potential to use such small amounts of metals that even an expensive metal like silver is not cost prohibitive.