Journal of Applied Polymer Science, Vol.127, No.3, 2235-2242, 2013
Simultaneous interpenetrating network silicone hydrogels prepared by free radical/cationic hybrid polymerization
Simultaneous interpenetrating polymer network silicone hydrogels have been prepared by UV-initiated polymerization of a mixture of methacrylate monomer 2-methacryloyloxyethyl phosphorylcholine (MPC) and vinyl ether terminated polydimethylsiloxane (VESi) macromonomer. The consumption of each (macro)monomer upon UV-irradiation was monitored in situ by real-time infrared spectroscopy. The methacrylate monomer MPC was shown to polymerize faster and more extensively than the vinyl ether terminated macromonomer VESi. Curing experiments performed in the presence of air and under air diffusion-free conditions indicated that the free radical polymerization of MPC was affected by the oxygen inhibition effect, while the cationic polymerization of VESi was influenced by the atmosphere humidity. The results of the transmission electron microscope studies indicated that the silicone hydrogels were heterogeneous with phase domain sizes less than 10 nm. The physicochemical properties of the silicone hydrogels, such as water content, ion permeability, oxygen permeability, and contact angle were also investigated. The results showed that water content and ion permeability increased with the MPC content in the formulation, and the silicone hydrogels exhibited excellent oxygen permeability with the highest Dk of 255 barrer. The contact angle measurements indicated that the silicone hydrogels possessed hydrophilic surfaces with the lowest water contact angle of 20 degrees. The result of the protein resistance revealed that the amount of protein adsorbed was significantly reduced with the MPC content in the formulation. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Keywords:UV-curing;silicone hydrogel;2-methacryloyloxyethyl phosphorylcholine;interpenetrating polymer network