Significantly enhancing electro-actuation performance of dielectric elastomer with ZrO2 nanoparticles

Dielectric elastomer is a kind of attractive artificial muscle with fast and reversible deformation excited by applied voltages. Typical dielectric elastomers suffer from low dielectric breakdown strength, which limits the achievable electro-actuation performance. We report that the introduction of surface-modified ZrO2 nanoparticles in dielectric elastomer (poly(styrene-b-butyl acrylate-b-styrene)) can significantly increase the dielectric breakdown strength. We highlight that the surface modifier molecules for ZrO2 nanoparticles should be designed to have an oligomeric chain compatible with the elastomer matrix to relieve the entropy loss of the elastomer chains. Thus, good dispersion of the nanoparticles can be achieved and the modulus is mildly increased. As a result, the maximum electro-actuation area strain is increased by a factor of 2.0 (from 19.1% to 37.8%), and the maximum energy density by a factor of 9.2 (from 5.96 kJ/m3 to 55.15 kJ/m3) by adding 1.7 vol% ZrO2 of 8 nm.