Photothermal and Humidity Stimulus-Responsive Self-Sensing Soft Actuators for Smart Packaging

Soft actuators with both actuation and self-sensing characteristics can better adapt to the environment and more effectively realize intelligent human–machine interactions, which is highly desired for the upcoming era of soft robotics. Herein, a multi-stimulus response actuator (MSRA) is constructed based on the asymmetric expansion principle, and the sensing function is simply and quickly integrated into the soft actuator by screen printing technology. Taking advantage of the good photothermal conversion performance of the dopamine-modified graphene oxide (DGO) layer and the difference in the expansion coefficient between the DGO layer and the poly(vinylidene fluoride)/polydimethylsiloxane layer, the soft actuators exhibit different actuation behaviors under photothermal and humidity stimuli, respectively. Meanwhile, the introduction of a printed carbon black/highly elastic transparent adhesive cement sensing layer gives MSRA a self-sensing function which can provide feedback on its actuation process in real time. In addition, various complex deformations can be achieved by the macroscopic assembly of several actuators. Finally, we show that this soft actuator can be used as a smart packaging material to realize smart packaging. We believe that actuators with sensing feedback are significant in soft robots and smart packaging.