▎ 摘　　要

Interface interactions between nanoparticles and polymer matrix have crucial effects on microstructures and properties. We demonstrate that polyurethane dielectric elastomer filled with titanium dioxide functionalized graphene, fabricated as a flexible micro-actuator, displays evident electric stimulus response and electric field induced strain. The hydrophilicity and wettability of graphene can be greatly enhanced by decorating nano-TiO2 onto graphene, which causes the improved interface interactions between fillers and polymers. Higher dielectric constant, less loss modulus, elevated breakdown strength, and better electric stimulation responses of the novel titanium dioxide functionalized graphene-polyurethane dielectric elastomer composite are achieved due to enhanced filler-matrix interface. The maximum electric induced thickness strain of this titanium dioxide functionalized graphene-polyurethane dielectric elastomer composite is 72.4% at 38.7 V/mu m, which is 1.8 times of the electric induced strain of graphene-polyurethane composite. (c) 2015 Elsevier Ltd. All rights reserved.