Electromechanical response of polyol-polyurethane blends as dielectric elastomer flexible mirco-actuator material

A simple, cheap, all-organic process for the fabrication of polyurethane (PU) composites for dielectric elastomer actuators was presented in this paper. This study focused on improving the electromechanical properties of PU matrix with polyol small organic molecule as filler. The dielectric, tensile mechanical, dynamic thermal mechanical, creep, and electric field induced strain properties of a series of polyol-PU blends were described in detail. It was found that the dielectric constant of PU at low frequencies (40–100 Hz) remarkably increased with the addition of polyols and the tensile strength of the PU/polyol blends decreased obviously with an increase in the content of polyol. The polyol-PU all organic composites had better electromechanical response than the pristine PU. Among the PU/glycerol, PU/ethylene glycol, and PU/triethylene glycol blends, PU/glycerol-50% had relatively high dielectric constant of 32.71 (40 Hz), low tensile strength of 16.37 MPa, low loss modulus of 164.24 MPa (−40 °C), high compliance of 9.709 × 10⁻⁵ 1/Pa, and high electric field induced strain of 49.7 (37.4 MV/m). The enhancement of the electric field induced strain was mainly triggered by an increase of the dielectric constant and a decrease of the elastic modulus.