Sweat gland-inspired skin soft actuators of the liquid crystal elastomer enabled by 3D printing

Human sweat glands can response to hot environment and autonomously discharge perspiration, taking away heat through evaporation. This biological feedback can affect the external stimuli, that is, reduce skin temperature. Inspired by the sweat gland, a skin actuator based on liquid crystal elastomer was fabricated. Benefit by the inherent properties of LCE, the actuator has the advantages of fast response and autonomous response without electronics. The actuator is obtained by direct ink writing printing of LCE ink. The actuation performance of LCE filament is optimized by adjusting printing parameters. The printing path is designed to achieve complex actuating deformation of LCE actuator. Two printed LCE components are assembled to obtain LCE chamber actuator. The influence of LCE chamber actuator with different shapes on the discharging capability is characterized. Array the LCE chamber actuators to obtain LCE skin actuator which can respond to overheating and locally discharge liquid to control the surrounding temperature. Benefit from the advantages of LCE and the structural design, the skin actuator can realize temperature control, which can maintain its surrounding temperature about 10 ℃ below the heating temperature. This work demonstrates the new opportunities for applications in temperature monitoring and local overheating protection.