Study on bending performance of flexible film based electro-thermal actuator

Flexible thermal actuators have a wide application prospect in the fields of bionics, medicine, and human-robot collaboration. In this paper, a flexible heat-driven actuator was fabricated, in which PE and PI films were used as the low expansion layer, PDMS film as the high expansion layer, and Cr20 Ni80 high-temperature Ni-Cr alloy wire was embedded between layers for heating. The two expansion layers produced different degrees of elongation at the same temperature, which resulted in the bending deformation of the actuator. The bending results showed that the steady-state deflections of the PE/PDMS and PI/PDMS actuators under a voltage of 5～9 V were 2～6.9 mm and 5.8～13 mm, respectively. The steady-state deflections of the two actuators increased and then decreased with the increasing thickness of PDMS film. The higher the voltage was, the faster the actuators were bent. Under a voltage of 9 V, the actuator provided a force as high as 12.2 mN. A mechanical claw made of the actuator successfully grasped an object of 2.2 times the weight of the claw.