Devices that respond to negligibly small fluctuations in environmental conditions will be of great value for the realization of more sustainable, low-power-consumption actuators and electronic systems.


Our developed film actuator seemingly operates autonomously, because it responds to the adsorption and desorption of a minute amount of water possibly induced by fluctuations in the ambient humidity. The actuation is extremely rapid and can be repeated times without deterioration. On heating or light irradiation, the film loses adsorbed water and bends quickly, so that it can jump vertically up from a surface.