Highly transparent and stretchable hydrogels with rapidly responsive photochromic performance for UV-irradiated optical display devices

Photochromic hydrogels have attracted considerable attention owing to their potential application in optical devices. However, the weak mechanical properties severely limited their applications. Here, a novel photochromic hydrogel with high transparency, high stretchability and rapid photochromic responsiveness has been successfully designed and prepared by introducing a redox photochromic material (Mo) into the hybrid hydrogel. The photochromic hydrogel with rapid photochromic response achieved discoloration process within only 3 s and the fading process could be easily performed under the air environment. Moreover, the ability to rewrite and erase optical information have been implemented on the photochromic hydrogels. Therefore, this strategy of photochromic hydrogel would contribute to design a new generation of optical display devices.