Enhanced electric field induced strain in electrostrictive polyurethane composites fibers with polyaniline (emeraldine salt) spider-web network

Abstract During the last decade, electrostrictive polymers have stood out especially in electromechanical applications because of their high-strain performance. The electrostrictive ability of a polymers is indicated by its electrostrictive coefficient (M) that depends on dielectric constant and Young's modulus. The dielectric constant of a polymer can be increased with fillers to create promising candidate materials for actuators and energy harvesting, because of interfacial polarization at matrix-filler interfaces. Therefore, a large specific interfacial surface is of importance. In this study, fibers were fabricated by electrospinning Polyurethane/Polyaniline (PU/PANI) composites with 0.5, 1, 1.5, or 2 wt% PANI loadings in the spinner. Then, morphology and chemical structure of the obtained fibers were investigated by SEM and FTIR, respectively. The electrical properties, mechanical properties, and electrostrictive properties were also evaluated. The results show that the average spun fiber diameter, its distribution, and occurrence of spider-web conformations depend strongly on the PANI content. Moreover, the dielectric constant increased with PANI loading and was inversely proportional to Young's modulus. The electrostrictive coefficient increased with PANI content and was for the spun fibers about 6 fold that of composite films, which was partly attributed to the spider-web conformations of the fibers.