Patent ID: 8541484

Claim:
A method of making a PVA-hydrogel comprising: a) contacting an aqueous solution of poly(vinyl alcohol) (PVA) with an aqueous solution of poly(acrylic acid) (PAA) at a temperature above the room temperature, thereby forming a homogenous PVA-PAA solution wherein the PVA-PAA solution includes no polyethylene glycol (PEG); b) pouring the PVA-PAA solution onto a mold followed by cooling down to room temperature, thereby allowing formation of the PVA-hydrogel; c) cooling the PVA-hydrogel by freezing at a temperature below 0° C.; d) thawing the PVA-hydrogel to a temperature above 0° C.; and e) immersing PVA-hydrogel in a PEG solution, thereby allowing diffusion of the PEG into the PVA-hydrogel.