Multi-responsive graphene quantum dots hybrid self-healing structural color hydrogel for information encoding and encryption

Information security plays an important role in the era of big data. Attempts to improve security often require giving them more additional encryption strategies. Herein, a specially designed multi-responsive graphene quantum dots hybrid self-healing structural color hydrogel system was proposed. Firstly, monomers such as N-isopropyl acrylamide (NIPAM), and dimethylamino ethyl methacrylate (DMAEMA) were filled into the photonic crystal templates and then photo-cured. After hydrofluoric (HF) etching, the graphene quantum dots (GQDs) and the precursor solution containing dithiothreitol (DTT) and borax were filled into the inverse opal holes. Finally, the hybrid hydrogel integrating quantum dots and photonic crystals was prepared by curing at room temperature. The hybrid hydrogel exhibited excellent pH, temperature, and angle-responsive color-changing characteristics. Besides, it had fluorescent properties under ultraviolet (UV) light irradiation and had photothermal conversion ability under near-infrared (NIR) light irradiation. Furthermore, the hybrid hydrogel color matrix was prepared by utilizing its excellent quantum dots fluorescent properties, dynamically adjustable structural color, multi-responsive, and self-healing properties. Therefore, the color matrix formed by the hybrid hydrogel had strong information storage capacity and encoding capacity, which could perform various information encryption and decryption modes step-by-step. Furthermore, we developed a simple mini-program for the step-by-step identification and decryption process of the matrix, indicating that it had great practical value in the field of information security.