Physically Linked PVA/P(AAm-co-SMA) Hydrogels: Tough, Fast Recovery, Antifatigue, and Self-Healing Soft Materials

The application of traditional chemically crosslinked hydrogels is often limited by poor mechanical properties because of their own inhomogeneous network and irreversible crosslinking bonds. Herein, physical interactions are applied to crosslink the interpenetrating network hydrogel, i.e., hydrogen bonding and crystalline domain for polyvinyl alcohol network, and hydrophobic interaction inside micelle for poly (acrylamide-co-stearyl methyl acrylate) [P(AAm-co-SMA)] network. In this gel network system, reversible energy dissipation mechanism is realized by dissociation and reassociation of weak interactions including hydrogen bonding and hydrophobic interaction inside the micelle. Strong crystalline domains serve as permanent crosslinking interactions to maintain network integrity under large extension. As a result, the synergy of weak and strong interactions leads to tough, antifatigue, fast recovery, and self-healing properties of the hydrogel. This proposed strategy of achieving versatile hydrogels can broaden the use of hydrogels into load-bearing applications.