Yu-Chin Lai

The role of bulky polysiloxanylalkyl methacrylates in polyurethane–polysiloxane hydrogels

Silicone hydrogels based on polyurethane–polysiloxane prepolymer and hydrophilic monomers such as N,N-dimethylacrylamide, although possessing high oxygen permeability and satisfactory tear strength, are too stiff to be targeted for applications such as contact lenses. However, with the inclusion of bulky polysiloxanylalkyl methacrylates, such as methacryloxypropyl tris(trimethylsiloxy)silane (TRIS), to replace part of the polyurethane prepolymer, the hydrogels obtained not only maintained high oxygen permeability, but also had a lower modulus and improved tear strength. These changes in properties are all favorable for applications such as oxygen-permeable hydrogel lenses.

Control of properties in silicone hydrogels by using a pair of hydrophilic monomers

Silicone hydrogels have been under intensive investigation for use in the biomedical field, especially as contact lenses. When silicone hydrogels were prepared using a combination of N-vinyl pyrrolidone and N,N-dimethyl acrylamide as the hydrophilic monomers, it was found that the surface wettability of these hydrogels can be improved with the mechanical properties and that water contents are in the acceptable range for certain applications, such as contact lenses.