A polyurethane-based elastomeric nanocomposite with a high dielectric constant

To increase the electric energy density of dielectric elastomer substantially, high dielectric constant nanocomposites were developed using polyurethane (PU) as matrix and copper phthalocyanine oligomer (CuPc)-a high dielectric constant organic semiconductor-as filler. Transmission electron microscope (TEM)-observed morphologies revealed that the sizes of CuPc particles in nanocomposite of PU chemically attached with 8.78 vol% of CuPc were in the range of 10-20 nm, much smaller than the sizes (250-600 nm) in the physical blend of PU with the same volume fraction of CuPc. At 100 Hz, the nanocomposite film exhibited a dielectric constant of 391, representing more than 60-fold increase with respect to the pure PU. The enhanced dielectric response of the nanocomposite 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 10 V/mu m).