Hierarchical metal/carbon nanotube-polymer composite films for amphibious photothermal actuators and power generation

In recent years, multi-functional actuators have caused concern owing to extensive possible applications in biomimetic and intelligent systems. Nonetheless, traditional light-driven actuators with bilayer heterostructure are mostly unsuitable for wading environments. Also, the heat generated can not be effectively utilized. Hence, there is an urgent demand for the progress of light-powered photothermal actuators which can not only be used in amphibious environments, but also utilize photothermal energy. To fill this gap, we designed amphibious light-powered actuators according to bilayer aluminum/carbon nanotube-polydimethylsiloxane (Al/CNT-PDMS) composite films with heterostructure. First, a light-driven actuator was designed according to the change in coefficient of thermal expansion (CTEs) between the layers. In the near-infrared (NIR) irradiation, its photothermal conversion efficiency could reach over 90 % with a maximum bending angle of 46.27°. Second, a floating light-powered actuator was designed according to the Marangoni Effect with a moving speed up to 16.7 mm s⁻¹. Further, the triboelectric nanogenerator (TENG) made from this composite film achieved an open-circuit voltage of 138 V. Finally, taking advantage of the above characteristics, the Al/CNT-PDMS actuators were used in a series of practical applications towards land and wading environments. These applications including bionic sunflowers, flexible switches, smart curtains, intelligent conveyor belts, and the self-powered light power sensors, demonstrating a broad range of appealing applications.