Paper BI+AS-TuA10
Surface Modification of Silicone Hydrogels through Adsorption of Diblock Copolymers

Tuesday, October 30, 2012, 5:00 pm, Room 23

The interaction between an ethylene oxide-block-butylene oxide (EOBO) copolymer surfactant and the surfaces of four silicone hydrogel (SH) contact lenses—PureVision® (PV), O₂OPTIX® (O₂), ACUVUE® Oasys ® (AO), and Biofinity® (BF)—was investigated using angle-resolved X-ray photoelectron spectroscopy (AR-XPS) following treatment in test solutions containing various concentrations of EOBO. The nature of this interaction was further understood by quantifying the amount of eluted EOBO from each lens following the same treatment using ultra performance liquid chromatography (UPLC). The elution study revealed a large disparity in the amount of EOBO uptake by the different samples following each solution treatment. The XPS results, however, suggested that the amount of EOBO retained on the surface of the lenses demonstrated a largely different trend. For example, AO and BF displayed little evidence of signal at binding energies characteristic of the EO blocks, whereas O₂ and PV exhibited a clear EO signature. The correlation between the elution and XPS results highlights the difference in the interaction mechanism of the EOBO copolymer with different lenses. For lenses such as O₂OPTIX®, this interaction is predominantly bound to the surface; for ACUVUE® OASYS®, however, EOBO was uniformly distributed through the lens structure.