Effects of conductive particles on the actuating behavior of dielectric elastomer actuator

Dielectric elastomers (DEs) are one particular type of electroactive polymers. Dielectric elastomers work as a variable capacitor. The effects of conductive particles on the actuating behavior of silicone rubber-based dielectric elastomer are studied in this work. Two different materials, which are carbon nanotube and carbon black, respectively, are used to increase the overall permittivity of the composites. Although the addition of these conductive particles increases the permittivity of the composite, they also produce a highly inhomogeneous electric field and reduced breakdown strength of the composite. This reduction in breakdown strength could be a serious drawback of nanocomposite approach. The main challenge, therefore, becomes how to enhance the permittivity of the composite while maintaining its high breakdown strength. These composites are characterized by dielectric spectroscopy, tensile mechanical analysis, and electromechanical transduction tests. The effect of variation in filler loadings on the complex and real parts of permittivity are distinctly visible, which has been explained on the basis of interfacial polarization of fillers in a heterogeneous medium. The phenomenon of percolation was discussed based on the measured changes in permittivity and morphology of composites at different concentrations of these particles.