Poly(vinylidene fluoroethylene-trifluoroethylene) based high performance electroactive polymers

This paper reports two classes of electroactive polymers developed recently which exhibit very high strain and elastic energy density. In the first class of the electroactive polymer, i.e., the defect structure modified poly(vinylidene fluoroethylene-trifluoroethylene) polymers, an electrostrictive strain of more than 5% and an elastic energy density above 1 J/cm/sup 3/ can be induced under a field of 150 MV/m. The large electrostrictive strain in this class of polymers originates from the local molecular conformation change between the trans-gauche bonds and all trans bonds, which accompanies the field induced transformation from the non-polar phase to the polar phase. The second class of the polymer is an all-organic composite, which shows a very high dielectric constant (>400) and high strain induced with a low applied electric field (2% strain under 13 MV/m). The strain is proportional to the square of the electric field and the composite has an elastic modulus near 1 GPa.