Reusable Shape‐Memory Photonic Crystal Paper for Pin‐Printing and High‐Resolution Press Printing

Rewritable photonic crystal (PC) paper has the potential to significantly reduce the consumption of forest resources in the printing industry, while also being environmentally friendly and efficient. However, traditional PC papers based on solvent or photothermal responses can lead to diffusion, which can hinder printing accuracy. In this study, a novel rewritable PC paper compatible with pin‐printing is presented based on a pressure‐responsive shape‐memory PC paper. High‐resolution printing can be realized by both computer‐programmed 3D‐printed seals and pin‐printing techniques. The information written on this PC rewritable paper can be erased by water, enabling the paper to be rewritten and reused at least 8 times without any change in performance. Furthermore, the information stored on the PC paper is stable and can be stored in ordinary environments for at least 6 months without fading. The PC paper has the capability of multicolor printing with a precision finer than 100 μm and has potential in office papers, smart price tags, and anti‐counterfeiting labels.