Composition dependent structural modulations in transparent poly(vinyl alcohol) hydrogels

Transparent and stable Poly(vinyl alcohol) hydrogels were synthesized from polymer aqueous solution without resorting to a mixed solvent such as dimethyl sulfoxide and water. Contrary to the reported methods involving hydrogen bond induced physical crosslinking by repeated freeze–thawing at −20 °C, the present process demonstrates the gelation taking place at relatively higher temperature, i.e. 0 °C. While maintaining transparency in all the synthesized hydrogels, the present paper reports systematic structural and morphological variations in the hydrogels as a function of polymer concentration.