Large electromechanical strain at low electric field of modified polyurethane composites for flexible actuators

• The modified PU composites filled with PANI were fabricated by solution casting.
• The modified PU/PANI-ES-HCl composite obviously provided large dielectric constant.
• The M33 of the modified composites increases by 20-fold compared to the neat PU.
• Large actuated strain at low electric field of the modified composite was obtained.

An electrostrictive polyurethane (PU) modified with three different polyaniline (PANI) loadings was demonstrated to overcome the limited actuated strains at low electric fields. The neat PU and all the composites were simply fabricated by solution casting. The experimental results show that high actuated strains (10.8%) at low electric fields (4.5 kV/mm) were observed for the modified PU/PANI-ES-HCl composite. In addition, the electrostrictive coefficient of the modified polymer increased by 20-fold compared to the neat PU. The modified PU/PANI-ES-HCl composites presented clearly a homogenous dispersion of filler in the polymeric matrix, and provided increased dielectric constant, high electromechanical response and low Young’s modulus. Consequently, this PU/PANI-ES-HCl composite is potentially a useful flexible material for actuators in low electric fields.