The design of membranes and bio-compatible hydrogels has been of intense interest to many companies. The question as to what is the solvent interaction and to what extent does an organic pollutant or solute interact has been of interest. Previous work has shown that either organic solvents alone or organic solvent/water mixtures can cause extensive hydrogel swelling1-3. This report covers the pH 3 and pH 10 swelling of 2-hydroxyethyl methacrylate based hydrogel and an examination of its interaction with aqueous n-propanol. In pH 10 water the methacrylic acid groups ionize and the repulsive ionic forces cause dramatic swelling. In addition the methacrylic acid groups are relatively hydrophobic while the salt is very hydrophylic. In pure, dry n-propanol the gel swells to only 0.8891 cm3/gm. The swelling of pHEMA gels requires good hydrogen bonding, oleophylicity and high dielectric components to the solvent. Combining the properties of a solvent such as n-propanol with water results in a media which has many of these properties.
Available at: http://works.bepress.com/michael-van-de-mark/36/