Insight into effect of hydrothermal preparation process of nanofillers on dielectric, creep and electromechanical performance of polyurethane dielectric elastomer/reduced graphene oxide composites

The electromechanical properties of diaphragm type actuator comprising hydrothermal reduced graphene oxide-polyurethane dielectric elastomer (RGO/PU) composites are described. Larger size graphene oxide (GO) nanoplates can be cut into smaller nanosheets during the hydrothermal conditions and the size of RGO nanosheets gradually decrease with pH value from 3 to 10. Small-size RGO nanosheets were introduced into PU dielectric elastomer matrix to obtain intelligent shape-changing polymer composites with high dielectric constant, high compliance and large electric field induced thickness strain. The RGO(pH10, 12 h)/PU-2.5 % composite film had a dielectric constant of 23.14 with a dielectric loss of 0.072 at 1 kHz. The composite film had a creep compliance of 3.211 x 10(-5) 1/Pa. At 38.5 MV/m, the electric field induced strain of RGO(pH10, 12 h)/PU-2.5 % is 56.5 %. The nanocomposites thus seem to be very attractive for Micro-Electro-Mechanical System applications.