Space-charge-enhanced electromechanical response in thin-film polyurethane elastomers

Abstract

We show that the large electrical-field-induced strain response observed in certain polyurethane elastomers is a thin-film effect. Based on the frequency dispersion of the strain response in samples with different thicknesses and the thermally stimulated discharge current on samples with different processing conditions, we suggest that the charge injection, an interface effect, which results in a nonuniform space-charge distribution and, hence, a nonuniform electric-field distribution across the sample thickness, is responsible for the enhanced electromechanical response in thin polyurethane samples.