Tough\nAdhesion of Freezing- and Drying-Tolerant Transparent\nNanocomposite Organohydrogels

Abstract

Tough\nhydrogels with strong wet adhesion have drawn extensive attention\nfor various applications. However, it is still challenging to achieve\nboth excellent wet adhesion and freezing- and drying-tolerance in\nhydrogels. In this study, we present tough transparent nanocomposite\norganohydrogels based on the glycerol–water binary solvent\nsystem in the presence of Al­(OH)₃ nanoparticles as a cross-linker.\nThe resultant organohydrogels exhibited excellent tensile strength\n(∼0.9 MPa), high transparency (97%), superior anti-drying and\nanti-freezing properties, and good ionic conductivity. In particular,\npolyacrylic acid (PAA) was chosen as the bridging polymer to endow\nthe organohydrogels with strong wet adhesion. The interfacial adhesion\nenergy exceeded 2200 J m^–2, which was ascribed to\nthe synergy of ionic coordination and hydrogen bonds between the nanoparticles\nand carboxyl groups in PAA chains. Interestingly, based on the strong\nwet adhesion, the transparent organohydrogels can be assembled into\nhydraulically driven soft variable-focus lenses with long-term ambient\nstability. This work will provide a new insight into controlled wet\nadhesion ̵of hydrogel and have great potential for hydrogel-based\nfunctional devices with long-term ambient stability.