Intelligent Switch Based on Controllable Adhesive Ionic Liquid Gel

Achieving on-demand bonding on different surfaces without residue on the bonded surface remains a major challenge for sustainability and intelligence of adhesive gels. Here, we demonstrate a temperature-controllable bonding strategy that utilizes π–π stacking and hydrogen bonding-driven stimulus-responsive reversible assembly to eliminate and activate interfacial interactions by modulating the bonding structure. Smart ionic liquid gels (ILGs) consisting of polydopamine (PDA), 1-butyl-3-methylimidazolium chloride ([BMIM]Cl), N-isopropylacrylamide (NIPAM), acrylamide (AM), and chemical cross-linking agent (MBA) were prepared by in situ free radical polymerization, where AM was used as the monomer of the gel networks, [BMIM]Cl was used as the internal dispersion medium, and NIPAM was the temperature-responsive structural unit. The adhesion strength of the ILGs is significantly affected by temperature, with an approximately 30 times difference between low (89 kPa) and high (3 kPa) temperatures when IL content is at 35 wt %. In addition, the ILGs have satisfactory underwater adhesion and self-healing properties and can be used for emergency repair of leaky holes in various materials. The innovative design of ILGs and the assembly strategy of functional materials expand their potential applications in various high-performance adhesive gels with smart switching and multifunctional integration.