A Soft Electrothermal Actuator with Large Deformation and High Periodic Deformation Speed

Recently, soft electrothermal actuators have attracted tremendous attentions. Large deformation under low driving voltage has long been the design concerns for scholars. However, in practice, apart from larger deformation, higher requirements are put forward for higher deformation speed in repeated cycles to achieve efficient and agile actuation. Herein, a soft electrothermal actuator is fabricated based on laser reduced graphene oxide and silver nanowire composite with polydimethylsiloxane substrate, which completely realizes the above required advantages. Besides, a concept of periodic curvature rate is proposed to accurately evaluate the deformation speed, which is more normalized than time alone to reflect before. The soft electrothermal actuator here can achieve a large curvature of 2.5 cm-1 with a high periodic curvature rate of up to 8.93×10-2 cm-1/s under low power density input of 0.8W•cm-2 (driving voltage of 28V), which shows obvious advantages in both deformation quantity and speed compared with most reported electrothermal actuators till now. Finally, a bionic hand consisting of five U-shaped electrothermal actuators is demonstrated to achieve gesture following and restoring, showing its promising prospects in the emerging bionics field.