Step Response Characteristics of Anisotropic Gel Actuator Hybridized with Nanosheet Liquid Crystal

In this study, we focus on a soft anisotropic gel actuator hybridized with nanosheet liquid crystal. This gel actuator is highly hydrophilic and can be operated underwater. Gel actuators can contract when heated and expand back to their original size when cooled down. It is anisotropic in the contraction direction, aligned with the orientation of the nanosheet liquid crystal. However, details of this step response property against the actuator undergoing thermal change have not been clarified. In this paper, we introduce a method to measure the step response using a square test sheet with a side length of 2–10 mm and thickness of 0.1–1.0 mm. This measurement was used to measure the heating and cooling step response. The obtained result was approximated using a first-order lag system to determine a steady-state value and time constant. In addition, the characteristics of steady-state value and time constant were clarified from the viewpoint of shapes such as specific surface area and thickness.