Biocompatible Polymeric Hydrogels with Tunable Adhesion to Both Hydrophobic and Hydrophilic Surfaces

Biocompatible polymeric hydrogels based on poly (vinyl acetate) (PVAc) and poly (methyl vinyl ether-co-maleic anhydride) (PMVE-MA) which demonstrated tunable adhesion to both hydrophobic and hydrophilic surfaces as ideal candidates for denture adhesives were prepared. PVAc was partially hydrolyzed in a mixed solvent of ethanol and water, and then mixed with PMVE-MA. Cross-linking between these two polymers through reactions between hydroxyl groups in partially hydrolyzed PVAc and maleic anhydride groups in PMVE-MA increased their compatibility, prevented their phase separation, and resulted in the transparent hydrogels. The adhesion of these polymeric hydrogels to hydrophobic and hydrophilic surfaces could be tailored by regulating the degree of hydrolysis of PVAc and the molecular weights of both polymers. The relationship between the adhesion of hydrogles and the degree of hydrolysis as well as the molecular weights of polymers was observed by rheology and the 180deg peeling test between wet cotton cloth and poly(methyl methacrylate) (PMMA) plate which mimic hydrophilic tissue surface and hydrophobic denture surface, respectively. The optimal adhesion appeared at the vicinity of critical gel point where the elastic modulus G\´ overlapped with the viscous modulus G". The crosslinking degree of the polymeric hydrogles was determined as 20 wt% by extracting the non-crosslinked polymers with acetone.