Rewritable Dual‐Mode Patterns Based on DASA Decorated PEG Crystal

Abstract Displaying the same data in different optical modes has improved both storage capacity and information security. However, it always requires either sophisticated chemistry or expensive experimental setup to build a dual‐mode or even multi‐mode anti‐counterfeiting system. Here, a rewritable dual‐mode pattern is designed, based on the second‐generation Donor‐acceptor Stenhouse adducts decorated polyethylene glycol crystal. Uniform square crystals are obtained through a simple process of controlled solvent evaporation. Complex pattern such as words can be written on the crystals with the help of microregional irradiation. It endows the high‐resolution of the pattern that only the area exposed to light goes through the discoloration and fluorescence change. The great reversibility and fatigue resistance of the photochromism enable the crystals to be repeatedly utilized, making them qualified candidates as high‐level anti‐counterfeiting materials.