Enhanced electro-actuation property of heterogeneous multi-layered polydimethylsiloxane-based dielectric elastomer composites

Due to their feature of the conversion from electrical to mechanical energy under an applied electric field, dielectric elastomers (DEs) have been widely adopted in smart devices. However, the significant electro-actuated property of DEs is always obtained under a giant driving electric field, which raises a potential safety hazard and limits their practical application range. Moreover, the traditional strategy of regulating the flexibility of DEs via physical swelling effect would result in an undesired plasticizer leakage and an irreversible reduction in both electromechanical stability and lifetime. Herein, a typical heterogeneous multi-layered polydimethylsiloxane (PDMS)-based DE composite was prepared by solution blending and the layer-by-layer casting method. Through synchronously introducing the high-permittivity BaTiO3 and the plasticizer dimethyl silicone oil in the middle layer, both the dielectric and mechanical property of the composite are effectively regulated. Not only the interlayered mechanical mismatch is eliminated but also the problem of plasticizer leakage is optimized through this reasonable structural design. The maximum electro-actuated strain obtained in the sandwiched DE composite was as large as 24.25% under 60 V/μm, which is 338.52% higher than that of pristine PDMS. Furthermore, the composite exhibits the largest driving strain (58.31%) near its breakdown electric field of 77.82 V/μm. Therefore, this study provides a promising route for the preparation of advanced DE composite with an improved low-field electro-actuated property.