A novel dielectric elastomer with low modulus and fast response

Dielectric elastomers (DEs) are highly valued in massive fields of actuators and sensors due to their unique advantages of large actuation strain, fast response speed, high energy density and excellent elasticity. The challenge of balancing the elastic modulus, actuation strain and response speed of DE actuators to stably enhance the actuation performance remains a major issue. In this work, a novel DE was prepared by employing polyurethane acrylate (CN9021) as a crosslinker, n-butyl acrylate as a base monomer and 2-ethylhexyl acrylate (2-EHA) as a functional flexible monomer via a UV curing method. The swelling test indicates a reduction of crosslinking density with the increment of 2-EHA concentration in EHA films. As a consequence, the elastic modulus displays a notable decline while the dielectric constant slightly rises, leading to an enhancement of the actuation sensitivity. More specifically, the elastic modulus of our fabricated EHA-1 is only one-third of the commercial VHB-4910. The developed DEs achieve an actuation strain of nearly 150% with low viscoelasticity and mechanical loss resulting in high response speed and broad operating frequency range to the input dynamic voltages. All these actuation performances are superior to VHB-4910. This work provides a promising strategy for developing DEs with balanced performance and superior actuation characteristics.