Low-loss polyacrylate dielectric elastomer with outstanding actuation performance by optimizing crosslinking network

This work reports the low-loss polyacrylate dielectric elastomer with outstanding actuation performance by employing a molecular engineering route. It is found that the difunctional macromolecular crosslinking agent we choose can not only effectively tune the dimensions of elastomer meshes and avoid uneven distribution of crosslinking points in elastomer matrix, accordingly eliminating the stress concentration and delaying the failure of elastomer, but also as “soft segments” and alleviate the strong dipole-dipole interaction between adjacent side groups of polyacrylate, which makes the dielectric elastomer with low elastic modulus and low mechanical loss. Simultaneously, a certain amount of uncrosslinked chains will remain in the free volume space of elastomer network, which would increase the dielectric constant of as-synthesized elastomers owing to their strong orientation ability. Therefore, the improvements in mechanical and dielectric properties of elastomer will contribute to the amelioration of actuation performance. We also design a home-made non-magnetic motor apparatus to verify the optimized actuation performance. This finding represents the first molecular engineering approach to improve the intrinsic actuation performance of dielectric elastomers, which are key materials of choice for flexible dielectric elastomer actuators.