Tough superabsorbent poly(acrylic acid) nanocomposite physical hydrogels fabricated by a dually cross-linked single network strategy

Abstract

Abstract In this work, we report a facile method for the preparation of tough and highly stretchable physical hydrogels by dual cross-linking composed of vinyl-hybrid silica nanoparticles (VSNPs) as multivalent covalent cross-linking and hydrogen bonding as physical cross-linking. Poly(acrylic acid) nanocomposite physical hydrogels (NCP gels) are obtained without adding any organic chemical cross-linkers. When the content of VSNPs is 0.7 wt% (relative to the monomer), the NCP gels exhibit good mechanical properties (fracture strength = 370 kPa, elongation at break = 2200%) and a high swelling capacity in both deionized water (2300 g/g) and saline (220 g/g). Meanwhile, the NCP gels have good recovery ability.