Elastomeric nanocomposites with high dielectric response

Abstract

Dielectric elastomers (DE) are one of the best-performing kinds of electroactive polymers which are highly desirable for use in a broad of electromechanical applications. At present, the need for high-driving electric fields limits the use of DE of potential applications. Increasing the dielectric constant of DE is a feasible approach to overcome this drawback. In this study, high dielectric constant nanocomposites were developed by bonding copper phthalocyanine oligomer (CuPc) to polyurethane (PU) chains. Transmission electron microscope (TEM) images revealed that the sizes of CuPc particles in nanocomposite of PU bonded with 8.78 vol% of CuPc were in the range of 10-20nm, much smaller than the sizes (250-600nm) in PU with the same volume fraction of CuPc. At 100Hz, the nanocomposite film exhibited a dielectric constant of 391, representing a ca sixtyfold increase with respect to the pure PU. The enhanced dielectric response of the nanocomposites makes it possible to induce a high electromechanical response under a much reduced electric field (a strain of 17.7% was achieved under a field of 10V/μm).