Polarographic Method for Measuring Oxygen Diffusivity and Solubility in Water-Saturated Polymer Films: Application to Hypertransmissible Soft Contact Lenses

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• 作者：Mahendra Chhabra ; John M. Prausnitz ; Clayton J. Radke
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2008
• 出版时间：May 21, 2008
• 年：2008
• 卷：47
• 期：10
• 页码：3540 - 3550
• 全文大小：239K
• 年卷期：v.47,no.10(May 21, 2008)
• ISSN：1520-5045

文摘

An electrochemical-polarographic method is described for measuring the diffusivity, D, and solubility, k, ofoxygen in aqueous-saturated polymer films. While the apparatus and procedure are general for such films, itis here applied to determine D and k for oxygen in hypertransmissible soft contact lenses. Usually, onlyoxygen permeability, P, the product of D and k, is measured because P gauges the steady flux of oxygenthrough hydrogel membranes. However, we utilize the polarographic technique in the unsteady state and,hence, obtain D and k separately. Determination of each of these properties is critical for designing betterlens materials that ensure sufficient oxygen supply to the cornea. We have measured oxygen diffusivities andsolubilities for nine commercial soft contact lenses. Our data indicate that oxygen diffusivity is primarilyresponsible for the range of oxygen permeability observed for hypertransmissible soft contact lenses. For2-hydroxyethyl methacrylate (HEMA)-based lenses, measured solubilities suggest that over 90% of thedissolved oxygen partitions to the polymer phase.