A Multi‐Functional and Rapid Responsive Photochromic Hydrogel for UV Indicators

Abstract

AbstractUltraviolet rays can cause serious damage to the skin and eyes, and in severe cases, it may lead to skin cancer. Therefore, the prediction, real‐time monitoring, and protection of ultraviolet rays is an important aspect of scientific research. Herein, a novel photochromic hydrogel is developed by using acrylic acid (AA) and 2‐(dimethylamino) ethyl methacrylate (DMAEMA) as the cross‐linking agent for hydroxyethyl methacrylate (HEMA) with the addition of microcrystalline 2,2‐diphenyl‐2H‐naphtho[1,2‐b] pyran‐6‐carbaldehyde (NP) for the real‐time monitoring and protection against ultraviolet rays. The binding mechanism of AA and DMAEMA is predicted using density functional theory (DFT). Also, the designed photochromic hydrogels exhibit excellent properties of pH and temperature sensitivity, rapid responsiveness, self‐healing, pressure resistance, high transparency, and electrical conductivity. The optical performance indicate that the photochromic hydrogel has a fast response to ultraviolet rays with color change occurring in 0.5 s and maximum color development in 5 s. In addition, the hydrogels show excellent compression resistance, and their residual stress decrease by only 0.85% after five cycles of compression. Therefore, it is hypothesized that the multi‐induction of these soft photochromic hydrogels could be applied in wearable devices, information storage equipment, display devices, and light printing.