A polyphosphazene elastomer containing 2,2,2-trifluoroethoxy groups as a dielectric in electrically responsive soft actuators

Abstract

The adaptive structure and excellent actuation of dielectric elastomer actuators (DEAs) make them promising candidates for soft robotics, haptic interfaces and artificial muscles. A wide variety of elastomers have been synthesised and investigated as dielectrics. Inorganic polymers such as polysiloxanes and polyphosphazenes have a low glass transition temperature. While polydimethylsiloxane (PDMS) has made its way into DEAs, the latter has received little attention in this field. Here, we present a dielectric elastomer based on polyphosphazene modified with 2,2,2,-trifluoroethoxy groups as the dielectric, which exhibits a dielectric permittivity two times higher than polydimethylsiloxanes (PDMS), excellent elasticity and a high dielectric breakdown field. These properties enable fast, reliable actuation and higher electrostatic forces than conventional PDMS. The actuators can withstand repeated actuation cycles and are suitable for long-term reliability applications.