(267c) Polymer Composites with Controlled Electrical Performance, Tunable Mechanical Properties, and Enhanced Processability: Rigid Materials to Flexible Elastomers

Electrically conductive polymeric materials have potential technological importance in the areas of energy storage devices, wearable communications, and robotics. To facilitate more widespread implementation, it is desirable to process these materials by common melt processing methods. Traditionally, conductivity has been obtained through either inherently conductive polymers or the addition of conductive filler. These methods often have a negative impact on the processability and end properties of the material. The rigid, conjugated backbones of many inherently conductive polymers produces very high melt viscosities or melt temperatures above the degradation temperature making them very difficult to process. In contrast, the incorporation of filler at the loadings required to obtain conductivity will dramatically increase the viscosity of the melt and alter the mechanical properties of the host polymer. To overcome these issues we have investigated two processing approaches. The first is to add eutectic metal that is molten at the melt processing temperature to have a minimal impact on the viscosity. After processing, the eutectic will remain solid over the entire anticipated operational temperature range. The successful incorporation of high eutectic metal loadings required the addition of more traditional nickel particulate filler. We have also developed a solvent assisted processing method to alter the bridge fraction and resulting mechanical properties of a thermoplastic elastomer while obtaining higher particle loadings than can be achieved using melt processing alone. We anticipate that this work will lead to implementation of conductive polymers into a wider variety of applications using traditional melt processing techniques.