Design and mechanism of photothermal soft actuators and their applications

Abstract

Photothermal soft actuators have become a hot research topic in recent years due to the unique light-to-heat conversion, mechanical deformation, contactless operation, and extended applications from bionic design to intelligent robots. Moreover, since superhydrophobic surfaces offer drag reduction, anticorrosive, and oil absorption properties, the synergistic effects expand their smartness in micro-robots, environmental remediation, bioengineering, transportation, wireless delivery, and oil spill recovery applications. In this review, we have provided an overview of soft actuators based on the photothermal effect. We begin with a comprehensive overview of the photothermal conversion mechanism and the photothermal actuation mechanism. It explores three different types of photothermal actuation, discussing their design and mechanisms. Furthermore, we focus on the latest advancements in photothermal soft actuators, categorizing them based on actuation mechanisms and addressing their significance and associated challenges. The photothermal soft actuators enable bionic-like soft movement in the horizontal and vertical directions through bending, contraction, and rotation in response to light-induced heat. Then, this review introduces various applications of photothermal soft actuators. Finally, we draw insightful conclusions and expose exciting new possibilities in the field of photothermal actuators to create innovative solutions for photothermal soft actuators that will eventually benefit society.