Tendril‐Inspired Programmable Liquid Metal Photothermal Actuators for Soft Robots

• Published in: Advanced functional materials 2024-01, Vol.34 (4), p.n/a
• Main Authors: Li, Xiaofei, Du, Yiming, Xiao, Chao, Ding, Xin, Pan, Xiaoshuan, Zheng, Kang, Liu, Xianglan, Chen, Lin, Gong, Yi, Xue, Meng, Tian, Xingyou, Zhang, Xian
• Format: Article
• Language: English
• Subjects: Actuators; Asymmetry; Bionics; bio‐inspired; Carrying capacity; Finite element method; liquid metal; Liquid metals; Microspheres; Morphology; Polytetrafluoroethylene; programmable photothermal actuator; Protoplasm; Robots; Soft robotics; soft robots; Thermal expansion
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202310380

Photothermal actuators are widely applied in robots, smart devices, and bionic systems. However, asymmetric thermal expansion, the most common mechanism for preparing photothermal actuators, has not been utilized in programmable liquid metal photothermal actuators. In this work, Liquid metal/Polyimide/Polytetrafluoroethylene (LM/PI/PTFE) programmable photothermal actuators based on asymmetric thermal expansion are prepared inspired by the climbing plant tendrils. The “protoplasm that can contract and bend” PTFE tape endows the photothermal actuator with programmable initial morphology. The photothermal properties and flexibility of the liquid metal microspheres, together with the significant property difference between PI and PTFE, endow the photothermal actuator with excellent response angles (130.74 ± 6.45°), response speeds (46.62 ± 2.33° s−1), stability (2000 cycles for 10 h), and load‐carrying capacity, which are not inferior to most of the reported PI photothermal actuators. The LM/PI/PTFE photothermal actuator has been successfully modelled and simulated by finite element analysis (FEA). Based on the programmable initial morphology and the simulation by FEA, this work has designed and prepared a variety of bionic systems and functional robots. The work of LM/PI/PTFE photothermal actuators provides a strategy for designing photothermal actuators and enables the future development of photothermal actuators in bionic systems and robots. Inspired by tendrils, programmable liquid metal photothermal actuators are prepared via the contraction of polytetrafluoroethylene (PTFE) and the interaction of liquid metal microspheres with polyimide (PI). With finite element analysis (FEA) and programmable morphology, soft robots with various functions are designed. The work provides a new strategy for designing photothermal actuators and sketches a promising future for them in soft robots.