A Novel Double-Network, Self-Healing Hydrogel Based on Hydrogen Bonding and Hydrophobic Effect

In this paper, acrylamide is used as a hydrophilic monomer, and octadecyl methacrylate (C18) and polyurethane (PU) monomers are used as hydrophobic monomers. In an aqueous solution containing mixed surfactants of cetyl trimethylammonium bromide and sodium dodecyl sulfate, a series of composite physical hydrogels with dual network structures are synthesized using these three monomers through in situ micelle copolymerization. The results indicate that, with the increase in PU content (<0.08 g), the thermal stability and mechanical properties (stretching and compressive) of the composite gel are enhanced, while the swelling performance becomes poorer. Furthermore, it can heal at room temperature and the self-healing property approaches 88% of that of the original sample after 60 min. Additionally, the self-healing efficiency shows a downward trend with the increase in the amount of PU, which is mainly related to the recovery efficiency of the network chain (polyacrylamide (PAAM) chain and PU chain) and the decrease in the mobility of C18. By constructing the double-crosslinked network, the design and preparation of polymer hydrogels with high stretching capability, good elasticity and self-healing performance provides a new approach to preparing hydrogels with excellent properties.