Design of a UV-responsive microactuator on a smart device for light-induced ON-OFF-ON motion

Combining a stimuli-responsive material and the Marangoni effect, a microactuator containing a ultraviolet (UV)-light-responsive photoresist and surfactant is fabricated. The locomotion of a functionally cooperating device loaded with the microactuator can be initiated by irradiation with 365 nm UV light, ceased by the removal of the UV light and restarted by re-exposure to the UV light. Moreover, the device exhibits good direction control via selective irradiation of photoresponsive microactuators at designated locations. This work is the first example using the chemical Marangoni effect to produce photoresponsive ON-OFF-ON motion of a macroscopic object on water surfaces with little impact on the experimental environment and opens up new opportunities for the design of novel advanced functional materials with controlled properties.