A Thermally Adjustable Multicolor Photochromic Hydrogel

Abstract

A rainbow of possibilities: A porous polymer gel undergoes light-triggered rapid two-state switching between two arbitrary structural colors at a controlled temperature (see picture; “on”: upon UV irradiation, “off”: in the dark). This switching is attributed to a change between two volume states. As the temperature also contributes to the degree of swelling of the gel, the color of the gel can be tuned thermally over a wide range of wavelengths.