Biomimetic soft actuator: Rapid response to multiple stimuli with programmable control

Stimuli-responsive soft actuators have attracted increasing attention in multiple fields since they exhibit unique advantages in safe interaction with humans and adaptability to dynamic environments. However, the study of untethered stimuli-responsive soft actuators has been limited by the slow response speed, irreversible deformations or inability in responding to multiple stimuli. Taking inspiration from the growth process of lotus leaves, we propose a novel design for an untethered soft actuator comprising graphene oxide (GO) and polyethylene (PE), which shows sensitive response to multiple stimuli, including moisture, light, heating, cooling, and elective volatile organic compounds (VOCs), and exhibits significant deformation at a rapid rate (up to 90.5°/s). The high sensitivity of the actuators enables them to be powered by the neglected energy in daily life instead of requiring specialized energy sources, paving the way for the green and sustainable development in soft robotics. In addition, the bending modes and bending degrees of actuators can be programmed to meet the personalized needs of complex three-dimensional structures. Based on GO/PE actuators, a variety of multi-stimuli-responsive intelligent devices have been developed to demonstrate their application potential in arts, bionics, soft robotics and wearable devices, including interesting WordArt, Chinese paper-cut art pieces, artificial iris, soft crawling robots and a smart cloth unit with adjustable breathability.