Spiropyran-Functionalized Hydrogels

Abstract

Photoresponsive actuators composed of a hydrogel functionalized with spiropyran are described. The hydrogel exhibits drastic shrinking in rapid response to blue light irradiation in acidic aqueous systems and is examined for the application of several photoresponsive actuator systems. Rodlike hydrogel bends drastically after 1 s light irradiation, and microrelief is formed instantly on the hydrogel sheet by the micropatterned light irradiation. Based on these characteristics of the hydrogel, a photo-controllable microfluidic system is constructed with a hydrogel sheet, and the microchannels with arbitrary width, height, and pathway are formed instantly by the micropatterned light irradiation. Also independent and parallel control of microvalve array by local light irradiation is demonstrated for a similar microfluidic system combined with fixed microchannel.