Maximum heat transfer rate density from a rotating multiscale array of cylinders

In recent years, multifunctional actuators have received increasing attention and development. In particular, researchers have conducted extensive research on intelligent actuators with integrated sensing functions. Temperature is an important parameter for the deformation of bilayer thermal actuators. By obtaining the temperature information of a bilayer thermal actuator, the deformation amplitude and its state can be judged. Thus, there is an urgent need to develop a type of intelligent actuator with a self-powered temperature sensing function. Herein, Ti₃C₂T_x-based composites modified with bamboo nanofibers have been proposed and applied to intelligent actuators integrated with a self-powered temperature sensing function. By utilizing the coefficients of thermal expansion between Ti₃C₂T_x-bamboo nanofiber composites and a polyimide film, a bilayer photo/electro-driven thermal actuator is designed which shows a bending curvature as large as 1.9 cm^-1. In addition, Ti₃C₂T_x-bamboo nanofiber composites have a Seebeck coefficient of -9.15 μV K^-1, and are N-type thermoelectric materials and can be used as the component of self-powered temperature sensors. Finally, a series of practical applications were designed, including a light-driven floating actuator (with a moving speed of 5 mm s^-1), biomimetic sunflowers, bionic tentacles, and a multifunctional gripper integrated with a self-powered temperature sensing function. In particular, the multifunctional grippers can output voltage signals carrying their temperature information without external complex power sources, demonstrating their potential for remote monitoring. The above results demonstrate that Ti₃C₂T_x-bamboo nanofiber composites have extensive practical applications in fields such as self-powered sensors, flexible thermoelectric generators, and soft actuators.