Photothermal Bimorph Actuators with In‐Built Cooler for Light Mills, Frequency Switches, and Soft Robots

• Published in: Advanced functional materials Vol. 29; no. 27
• Main Authors: Li, Jingjing, Zhang, Rui, Mou, Linlin, Jung de Andrade, Monica, Hu, Xiaoyu, Yu, Kaiqing, Sun, Jinkun, Jia, Tianjiao, Dou, Yuanyuan, Chen, Hong, Fang, Shaoli, Qian, Dong, Liu, Zunfeng
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01-07-2019
• Subjects: Actuation; Actuators; Automation; Beam theory (structures); bending actuation; Broadband; Electromagnetic absorption; Evaporative cooling; Finite element method; Flapping wings; light mills; Manufacturing engineering; Materials science; photothermal; Polymer matrix composites; Polymers; Response time; Robots; Shrinkage; Soft robotics; soft robots; Switches; Temperature gradients; torsional actuation; Walking
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.201808995

Photothermal bimorph actuators are widely used for smart devices, which are generally operated in a room temperature environment, therefore a low temperature difference for actuation without deteriorating the performance is preferred. The strategy for the actuator is assembling a broadband‐light absorption layer for volume expansion and an additional water evaporation layer for cooling and volume shrinkage on a passive layer. The response time and temperature‐change‐normalized bending speed under NIR, white, and blue light illumination are at the same level of high performance, fast photothermal actuators based on polymer or polymer composites. The classical beam theory and finite element simulations are also conducted to understand the actuation mechanism of the actuator. A new type of light mill is designed based on a wing‐flapping mechanism and a light‐modulated frequency switch. A fast‐walking robot (with a speed of 26 mm s−1) and a fast‐and‐strong mechanical gripper with a large weight‐lifting ratio (≈2142), respectively, are also demonstrated.
A photothermal bimorph actuator with an in‐built cooling and thermal‐contraction layer is designed and exhibits excellent actuation performance under multilight stimuli. The actuator shows applications in light‐modulated frequency switching, fast crawling robots (with a speed of 26 mm s−1), fast‐and‐strong mechanical grippers with a large weight‐lifting ratio (≈2142), and light mills based on a wing‐flapping mechanism.