Monday, April 30, 2007

Oxygen permeability of poly(sorbitan methacrylate) hydrogel

Seok-Hwan Park1, Gwi-Taek Jeong2, Hee-Seung Yang2, Jae-Hee Park2, Kyoung-Min Lee2, Do-Heyoung Kim3, Doman Kim2, Changshin Sunwoo2, and Don-Hee Park2. (1) Interdisciplinary Program of Graduate School for Bioenergy & Biomaterials, Chonnam National University, Gwangju, South Korea, (2) School of Biological Sciences and Technology, Chonnam National University, Gwangju, South Korea, (3) Faculty of Applied Chemical Engineering, Chonnam National University, Gwangju, South Korea

The major materials which used for commercialized soft contact lenses today are hydrogels. Sugar esters which contain sugar molecules have been receiving increased amounts of interest, and are already being utilized in several fields in a variety of applications. Characteristics of contact lens material are oxygen permeability, oxygen transmissibility, equivalent oxygen percentage, moisture content, surface wet ability, and refractive index. The change in water content of a contact lens changes oxygen permeability. The moisture content of hydrophilic contact lens is important propensity that decides other characteristic. In this study, The objective of this experiment is to measure moisture content and oxygen permeability in poly(sorbitan methacrylate) hydrogel. Poly(sorbitan methacrylate) is synthesized by free radical polymerization from sorbitan methacrylate. The oxygen permeability is measured with degrees of refractive power. A reduction in water content as temperature is raised, will be expected to decrease oxygen permeability. However, increasing the temperatures leads to an increase in the diffusion coefficient. In general, they showed that the decrease in water content will be about 2.5% units when the temperature is increased from 21 to 35C, which is consistent with Kohler and Flanagan.