Synthesis of Polyglycidol Hydrogel Films Crosslinked with Carboxyl-terminated Poly(ethylene glycol)

With the attempt to largely increase the water content while keeping mechanical properties, hyperbranched polyglycidol (PGLD) hydrogel films were prepared using the oligomeric crosslinking agent, carboxyl-terminated poly(ethylene glycol) (PEG) of different molecular weights. Both the swelling and mechanical (tensile) properties of PGLD hydrogels crosslinked with PEG were measured and compared with the previous glutaric acid crosslinking system. The resultant PGLD films showed higher gel fraction and greater swelling capacity even at low PEG concentrations compared to those crosslinked with glutaric acid, probably due to the combined effect of the hydrophilicity and long chain effect of the PEG crosslinker. The values of the Young's modulus and tensile strength were also higher for crosslinked films from PEG than from glutaric acid at a given (lower) crosslinker concentration. In addition, both the swelling and tensile properties of the PGLD hydrogels were largely affected by the crosslinker concentration.