Multicolor photochromic material with dual protection of anti-counterfeiting and waterproofing

Optical information storage materials with dual protectiveness of anti-counterfeiting and waterproofing are critical to store information and improve paper utilization in a safe and accurate way. A novel multifunctional material with efficient photo-responsiveness and hydrophobicity was herein developed. Wherein, a system of silver ion (Ag+)/polyoxometalates/polymer was creatively formed as a photochromic layer, achieving different color variations by different contents of Ag+ and UV irradiation doses. This functional surface can maintain colored state for a long time in indoor environments, which is favorable to long-term information storage. It can be quickly blenched within 20 min under a hydrogen peroxide-containing atmosphere, achieving controllability of fading time. In addition, a multifunctional transparent coating formed by PDMS and fine particles composed of ytterbium compound and silica was applied on photochromic layer. This coating rapidly generates dazzling green light under infrared radiation, laying a foundation for the safe transmission of information. Its microstructures effectively capture air in gaps and low surface energy avoids wetting of water, achieving excellent hydrophobicity with a surface contact angle of 152°. In a word, this elaborately designed strategy for information storage via photochromism and dual protection shows enormous application potentials in optical information storage and encryption.