Multilayer Graphene/PDMS Composite Gradient Materials for High‐Efficiency Photoresponse Actuators

Smart actuating materials have a wide range of applications in artificial muscles, soft robots, and flexible electronics. The preparation of highly sensitive and reliable actuators is a top priority in this regard. In this work, a multilayer graphene/polydimethylsiloxane (PDMS) composite gradient material is designed and prepared by a simple in situ stacking and curing method for high-efficiency photoresponse actuator. The typical gradient structured material consists of a pure PDMS film and multiple graphene/PDMS composite films with monotonically varying graphene concentration. Attributed to gradient structure design and high photothermal conversion efficiency of graphene, the actuator shows the enhanced photoresponse properties. Through theoretical modeling, finite element analysis and experiments, it is confirmed that with increasing the stacked layer number at the same total thickness, the gradient structured actuator can present a better actuation performance. In addition, the film thickness and the concentration of graphene are also found to have an obvious effect on the actuating behavior, enabling the deflection over 90 degrees. The applications of the actuator as a cantilever beam, a soft crawling robot and a smart gripper are also demonstrated. This provides a new design idea for further improving the actuation performance of the soft actuator.