Multifunctional Untethered Soft Machines Driven by 4D Printed Electrically Responsive Actuators.

Untethered robots, compared with their tethered counterparts, may bring enhanced autonomy. It is highly desirable to engineer multifunctional, lightweight, rapid, and low-voltage driven untethered soft robots that have enhanced adaptability and safer interaction capabilities. Here we present an untethered soft robot by a smart integration of 4D printed liquid crystalline elastomer (LCE) actuators with the associated electronics. The LCE artificial muscle, which consists of a modified LCE sandwiched between a polyimide based heating film and a silicone adhesive, not only has adjustable transition temperatures (39-46 °C) and modulus (0.61-2.57 MPa) but also has decent mechanical properties such as adequate rigidity to support certain loads and sufficient propulsive forces (13.7 MPa) to facilitate robotics motions. As a result, we developed an untethered, compact LCE soft robot that is the lightest (overall weight of 9.87g) and the quickest (0.28 body length per minute), and has the lowest cost of transportation (CoT of 7), among all untethered electric-driven LCE robots. The LCE robot can also be used for grasping and demonstrating obstacle crossing capability on challenging terrains.