Hygro‐Dynamic and Conductive Actuator That Restructures and Heals by Water

Abstract The prospects of endowing stimuli‐responsive materials with various life‐like behaviors are promoting the development of intelligent robotic and electronic devices. However, it is challenging to incorporate stimuli‐responsive actuating and healing capabilities into one single material system. Herein, the design and assembly of humidity‐responsive thin films composed of poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) and sodium carboxymethyl cellulose (NaCMC) forming a conducting polymer composite through a physically cross‐linked and hydrogen‐bonded supramolecular network are described. Owing to its enhanced dynamics of hydrogen bonding at an elevated humidity, the PEDOT:PSS/NaCMC thin film exhibits a rapid humidity‐responsive actuating performance in an environment with humidity gradient, as well as a repairing function of the structural, mechanical, electrical, and actuating properties after being damaged through a humidifying‐drying cycle. Based on a combined analytical approach, a structural model is proposed for the rearrangement of the thin film when being exposed to stepwise humidity levels at multi‐length scales. Due to the structural rearrangement powered by humidity variations, the film exhibits tunable actuating and healing performance, which makes it a promising candidate material for applications in intelligent soft robotics such as artificial muscles.