Enhancing Dielectric Performance of Acrylate-Based Elastomers via Incorporation of Polar Cyano Groups

Dielectric elastomers (DEs) are a class of flexible intelligent materials capable of significant deformation under external electric field stimulation. However, conventional DEs typically exhibit low dielectric constants, necessitating the application of excessively high electric field strengths (>100 kV/mm) to achieve substantial actuation. In this work, we design a series of poly(butyl acrylate-co-acrylonitrile) (PBA-AN) copolymers by introducing polar cyano groups (-CN) from acrylonitrile (AN, key polar monomer) into a butyl acrylate (BA)-based matrix, and systematically optimize the molar ratio of BA to AN. The optimal copolymer composition (PBA₇₀-AN₃₀, 70 mol% BA and 30 mol% AN) endows the DE with a balanced combination of high dielectric performance and superior actuation characteristics: a high dielectric constant of 10.89 at 1 kHz, a low dielectric loss tangent of 0.0197, and a reduced Young's modulus of approximately 0.106 MPa. At a low electric field strength of 30 kV/mm, these DEs achieve an area strain of 20%, a 4.4-fold enhancement compared to the commercial material VHB4910 that only delivers an area strain of 4.5% under identical conditions. This study presents a novel approach to the fabrication of high-performance acrylate-based DEs.