Deformation- and temperature-responsive elastomer composites for smart device applications

the electrical behavior of conducting carbon whisker reinforced thermoplastic elastomer (TPE) composites was investigated. The carbon whiskers were produced by a catalytic chemical vapor deposition (CCVC) process. The electrical properties of the composite were characterized as a function of temperature and deformation. The electrical resistivity of the composite can be varied by uniaxial deformation and by temperature. The temperature-resistivity studies indicated that the resistivity of these composites were influenced by the glass transition temperature of the TPE. the resistivity v. 1/T curves exhibited two distinctive negative slopes that intersected at the Tg of the elastomer. This as correlated to the Tg of the rigid segments in the TPE as obtained by the dynamic mechanical thermal analysis. Further, uniaxial deformation studies at room temperature demonstrated that the resistivity increased exponentially with the deformation. Mechanical and electrical properties of the composites indicated that CCVD carbon whiskers can be used to improve the strength and electrical conductivity of TPEs. The change is resistivity (up to 5 orders of magnitude) of the composites with respect to deformation and/or temperature can find use in electromechanical and electrothermal applications.