Ultra high permittivity and significantly enhanced electric field induced strain in PEDOT:PSS-RGO@PU intelligent shape-changing electro-active polymers

Large deformation of soft materials is harnessed to provide functions in the nascent field of soft machines. In this work, PEDOT:PSS noncovalent functionalized graphene-polyurethane dielectric elastomer composites (PEDOT:PSS-RGO@PU) have been synthesized as promising candidate materials for micro-actuator electromechanical applications. PEDOT:PSS conducting polymer chains not only reinforce the interaction between the polyurethane matrix and graphene sheets, but also prevent graphene sheets from aggregating and connecting, which are beneficial to forming microcapacitors in the matrix and suppressing the leakage current. The PEDOT:PSS-RGO@PU composite exhibits ultra high permittivity (350 at 1 kHz), low dielectric loss (similar to 0.2 at 1 kHz), low loss modulus (200 MPa), and low loss tangent (similar to 0.4), all being essential to create a high performance electric-induced strain material. The maximum thickness strain of 164% is significantly higher than reported values for polyurethane elastomers and nanocomposites.