Towards Ultrasonically Actuated Programmable Polymorphic Soft Actuator

The development of an untethered soft actuator that can perform complex task under external control is highly desirable. In this work, we present an ultrasonically actuated programmable polymorphic soft actuator scheme and demonstrate the untethered polymorphic actuation of the proof-of-concept device. The ultrasonic actuation is enabled through converting the incoming ultrasonic energy to thermal energy by the Joule heating. The temperature increase triggers shrinking of the thermally responsive hydrogel/polymer bimorph. By employing two ultrasonic receivers with different resonant frequencies (frequency coding), we demonstrated 4 different motions of the actuator.