2, Arizona State University, Tempe, Arizona, United States
4, University of Arizona College of Medicine, Tempe, Arizona, United States
5, Arizona State University, Tempe, Arizona, United States
3, University of Arizona, Tempe, Arizona, United States
Stimuli-response hydrogels have found tremendous applications as adaptive lenses, artificial muscles, vehicles for drug deliveries, scaffolds or matrices for tissue engineering, as well as sensors and actuators for soft robotics and soft machines. Here we report a tough, conductive, multi-responsive hydrogel, which is designed and synthesized by one-step polymerization with double network made of conductive polymer and chemically nano-crosslinked hydrogels. This hydrogel possesses a highly mechano-electrically sensitive that can change shape rapidly at large ratios upon local sensing of the approaching of an arbitrary object in contact with the hydrogel. This smart hydrogel can change its volume in response to subtle mechanical force and electric signals like the neural commands and acute tactility of octopus or human skin when it is in contact with an object. This presents a novel capability of force-induced shape changing, achieved through the force-electro-mechanical energy transduction within the gel materials. Overall, the important novel characteristic of this force-sensitive tactile hydrogel is the capability of detecting the geometry or rigidity of the environment and adaptively changing its own shape to adapt to the shape of the environment. For example, such gel can behave as a fully automatic gripper without external control, which can grasp an object in arbitrary shape that is poking the gel. Additionally, this hydrogel is highly strong mechanically. Unlike previously developed pneumatic or hydraulic soft robotic arms and manipulators, our tactile hydrogel-based robotic materials will be self-contained and capable of continuous “sense-diagnose-response” to perform adaptive configuration changes without incurring damage.