Facile preparation of hydrogen-bonded supramolecular polyvinyl alcohol-glycerol gels with excellent thermoplasticity and mechanical properties

Facile preparation of tough hydrogels with excellent processability is of great practical importance, but it remains a great challenge. A novel type of hydrogen-bonded supramolecular PVA-glycerol gels is prepared with a very simple physical mixing method, in which glycerol molecules connect PVA chains into bundles by forming many H-bonds. The PVA-glycerol gels show much higher transparency than common PVA gels, due to their lower crystallinities and nanosized microstructures. The physical crosslinking nature and easy gelation at room temperature endow the gels with excellent moldability and thermoplasticity. The easy breaking of the H-bonding provides an effective energy-dissipating mechanism, leading to the high tensile strengths (up to more than 2 MPa), moduli, toughness and fracture energies of the gels. The PVA-glycerol gels also exhibit weaker temperature-dependent mechanical behaviors and excellent cold-resistance. The easy preparation and excellent properties of these gels should facilitate the practical applications of tough gels in many fields.