As one of the most promising candidates for dynamic information storage, intelligent gels with tunable optical properties under external stimuli have received great attention. The implementation of transparency variation for information display is a favorable and versatile strategy but still faces the challenge of on-demand encryption–decryption. Herein, an optical tunable organohydrogel is prepared, which has interpenetrating heterogeneous networks consisting of hydrophilic poly(N,N-dimethylacrylamide) (PDMA) and hydrophobic polyoctadecyl methacrylate (PSMA). The long alkane side chains of PSMA endow the organohydrogel with the capacity of crystallization–melting transitions under the stimulus of heat, accompanied by transparent–opaque switching. In addition, the variations of transparency can also be achieved by water-induced hydrophobic association and microphase separation, resulting from the unique heterogeneous networks of the organohydrogel. Based on the abovementioned two aggregated structures, various pieces of information can be loaded on the organohydrogel by light writing or water printing with the assistance of masks. The coded information can be encrypted and decrypted by solvent replacement and temperature switching. This elaborately designed organohydrogel can act as an effective communication platform with an improved security level and ignite the sparks of developing novel information storage materials.
Flexible sensors have been widely studied for their huge potential applications in health monitoring, soft robots and electronic skin. However, the simple and rapid preparation of Janus-type flexible adhesive sensors with adhesive properties on one side and no adhesive properties on the other side is still a great challenge. In this work, we first used the different solubilities of silk fibroins in water and the hydrophobic ionic liquid 1-ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl] ([EMIM][Tf2N]) to prepare Janus-type ionic conductive gels by a “one-step” method of UV irradiation. In this system, the noncovalent bond interaction between poly(N,N-dimethylacrylamide) (PDMA) and [EMIM][Tf2N] and the substrate endows the gel with strong adhesion, and the ionic liquid [EMIM][Tf2N] endows the gel with conductivity and bactericidal properties. However, silk fibroins in ionic gels have a ladder distribution due to different solubilities and are concentrated on the other side of the gel so that the side of the gel does not have adhesion. Additionally, the β-sheet structure of silk fibroins gives the ionic gel greater toughness. Janus-type ionic conductive gels prepared by this method have super tensile properties (2671%), excellent bactericidal properties (99.99%) and strong adhesion to a variety of substrates (such as glass, rubber, metal, and plastic) and skin. Moreover, the Janus-type ionic conductive gel has excellent electromechanical properties, such as good sensitivity, low hysteresis and good repeatability, when used as a sensor and can realize multifunctional detection of the human body's various strain movements and pressure changes. Based on the simple and easy-to-operate preparation method and the endowed excellent electromechanical characteristics of the Janus-type ion-conductive gel, it has broad application prospects in the fields of multifunctional wearable sensors.
危险品化学品经营许可证（带存储）