Self-healing clay-polymer composite hydrogel obtained by evaporation induced cross-linking and subsequent anisotropic swelling

Abstract

Thanks to the dispersibility of smectite and solubility of poly(vinyl alcohol) (PVA) as well as the biocompatibility of both components, smectite-PVA composites have been examined for various applications. A synthetic hectorite (Sumecton SWF)-PVA sheet was obtained by a drying of an aqueous mixture of the components at room temperature. Cross-linking of PVA was achieved during the evaporation of solvent (evaporation-induced cross-linking). The sheet was immersed in water to obtain a hydrogel sheet. Based on the unique anisotropic swelling of the present hydrogel, the self-healing induced by water of the hydrogel was achieved. The healing was done within 3 s. The SWF-PVA hydrogel composite, prepared by using the novel cross-linking method, exhibited anisotropic swelling and water-induced self-healing.