A bionic intelligent hydrogel with multi-level information encryption and decryption capabilities

Information security has evolved into an indispensable facet of modern society, attracting enormous attention to diverse encryption techniques. Nevertheless, the pressing need persists for the development of intelligent materials that can offer multi-level information encryption and decryption, incorporating various implementation methods as well as automated encryption following the retrieval of target information through decryption. To address this, inspired by the intelligent color-changing camouflage strategy of chameleons, we propose a multi-stimulus responsive color-changing intelligent hydrogel (PHALSD). By introducing sodium dodecyl sulfate (SDS) to mimic the pigment cells in chameleon skin and employing temperature/pH as responsive stimuli, the SDS disperses or aggregates to form micelles within the hydrogel matrix, thereby changing its color. This mechanism imitates the chameleon's alteration of coloration, wherein external stimuli provoke the dispersion or clustering of pigment cells, resulting in a change in its color. The PHALSD exhibits high transparency, remarkable mechanical performance, and exceptional electromechanical properties. Building upon this foundation, several information encryptions and decryption devices have been developed, including a two-dimensional (2D) code-based device for dual-level encryption and decryption, a multi-level information encryption and decryption device that seamlessly integrates information with the surrounding environment analogous to the biological process of chameleon's intelligent color-changing camouflage, and a barrier-free communication system specifically designed for amyotrophic lateral sclerosis (ALS) patients utilizing PHALSD strain sensors and information encryption/decryption strategies.