LAUSR

A straightforward strategy is first proposed to prepare an optical hydrogel film with dynamic structural colors. This was achieved by entrapping a dry thermoresponsive microgel film in a thermoresponsive matrix hydrogel to construct a hierarchical structure. The color-displaying function is implemented by the synergistic effect of both microgels and the matrix hydrogel in which the microgels change their sizes by temperature stimuli while the thermoresponsive matrix hydrogel keeps them in a close-contacted state. The disordered microgel arrays endow the composite hydrogel film with angle-independent structural color. The dried stimuli-responsive microgel film and same thermoresponsive surrounding hydrogel are two crucial issues. Based on this concept, a pH/thermo dual-responsive optical hydrogel film was further prepared by introducing methacrylic acid, a pH-sensitive co-monomer into the microgels and matrix hydrogel. This straight and convenient fabrication strategy may open up a new route for preparing optical hydrogel films with various functions.