Dynamic metal-ligand coordination enables hydrogel with rewritable dual-mode pattern display

Abstract

The realization of dual-mode information display in the same material is of great significance to the expansion of information capacity and the improvement of information security. However, the existing systems lose the ability to re-encode information once they are constructed. Here, the dynamic metal-ligand coordination is introduced into a novel hydrogel-based optical platform that allow rewritable dual-mode information display. The hydrogel system consists of hard lamellar structure of poly(dodecylglyceryl itaconate) (pDGI) and soft double networks of poly(acrylamide)/poy(acrylic acid) (PAAm/PAAc) containing fluorescent carbon dots (CDs). As the carboxylic acid groups can coordinate with metal ions such as Al3+, the layer spacing of lamellar structure is reduced while CDs aggregate, leading to the blue shift of structural color and the red shift of fluorescent color. Additionally, the metal chelating agent, ethylene diamine tetraacetic acid (EDTA), is able to strip away Al3+ ions and restore the two colors, realizing erasable dual-mode information display. This study opens up a path for the development of new materials and technologies for rewritable dual-mode information protection.