Effect of Filler Materials with Different Cross Sections on the Performance of Dielectric Polymer Actuators

Electroactive polymers with quick response time, suitable for most actuator applications, are broadly classified into three categories: Piezoelectric polymers, Dielectric elastomers and electrostrictive polymers. Among the above three, dielectric elastomers polymers offer the best performance characteristics. It is well known that the underlying microstructure influences the overall properties of a composite. In this regard, our first objective here is to investigate the effect of volume fraction and distribution of high dielectric constant (K~10000) filler particles on the overall dielectric constant of EAP composites. The filler particles are taken to be cylindrical with circular cross-sections and the dielectric behavior of the phases is taken to be linear. Both random as well as periodic microstructures are analyzed. More specifically among the periodic microstructures, a square and hexagonal arrangement of cylindrical fibers is considered. In experiments, nano-composite containing very high dielectric constant inclusions is shown to result in very high overall dielectric constant at volume fractions less than 10%.