Soft, tough, and fast polyacrylate dielectric elastomer for non-magnetic motor

Abstract

Abstract Dielectric elastomer actuators (DEAs) with large electrically-actuated strain can build light-weight and flexible non-magnetic motors. However, dielectric elastomers commonly used in the field of soft actuation suffer from high stiffness, low strength, and high driving field, severely limiting the DEA’s actuating performance. Here we design a new polyacrylate dielectric elastomer with optimized crosslinking network by rationally employing the difunctional macromolecular crosslinking agent. The proposed elastomer simultaneously possesses desirable modulus (~0.073 MPa), high toughness (elongation ~2400%), low mechanical loss (tan δ m = 0.21@1 Hz, 20 °C), and satisfactory dielectric properties ( $${\varepsilon }_{{{{{{\rm{r}}}}}}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mrow> <mml:mi>ε</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>r</mml:mi> </mml:mrow> </mml:msub> </mml:math> = 5.75, tan δ e = 0.0019 @1 kHz), and accordingly, large actuation strain (118% @ 70 MV m −1 ), high energy density (0.24 MJ m −3 @ 70 MV m −1 ), and rapid response (bandwidth above 100 Hz). Compared with VHB TM 4910, the non-magnetic motor made of our elastomer presents 15 times higher rotation speed. These findings offer a strategy to fabricate high-performance dielectric elastomers for soft actuators.