Modified Silicon Rubber Of Controlled Bacterial Contamination For Contact Lenses Applications

Abstract

This thesis deals with the modification of silicone rubber based hydrogels manifesting the comfort and wearability for use in contact lenses application. Silicone rubber was modified by three different techniques to obtain silicone hydrogel (SiH) biomaterials possessing hydrophilic and antibacterial properties for contact lenses application.

First technique: Interpenetrating polymer network (INP)

Polydimethylsiloxane (PDMS), a type of silicone rubber mostly used in biomedical devices, was modified into ultraviolet-curable PDMS- polyurethane (PDMS-PU) prepolymer, then INP silicone hydrogels consisting of ultraviolet- curable PDMS-PU prepolymer, 3-methacryloxypropyl tris(trimethylsoloxy silane) (TRIS) and hydrophilic monomers N,N-dimethyl acrylamide (DMA) and polyethylene glycol methacrylate PEGMA were formed.

Second technique: Graft copolymerization of PDMS through photo-polymerization

Grafting copolymerization of PDMS, having methacryloxy side chain, with different concentrations of DMA and N-vinyl pyrrolidone was done by free radical polymerization. The chemical groups of these silicone hydrogels formed by IPN and grafting copolymerization techniques were characterized by FTIR. Their tensile modulus, protein adsorption, equilibrium water content and water contact angle were also measured. It was found that the equilibrium water content enhanced when the hydrophilic monomer content increased, while their protein adsorption, tensile modulus and water contact angle decreased.