Abstract
The effects of salinity and temperature on the release of the quaternary ammonium compound, benzalkonium chloride (BAC), from a poly (2-hydroxyethyl methacrylate) (PHEMA) hydrogel were studied. Previous research had shown that such a combination produced a transparent coating, which demonstrated reduced biofouling properties in a marine environment. Release was monitored at two salinities, low (4 parts per thousand) and normal (35ppt) which is the approximate salinity of natural seawater, as well as at four temperatures 5°C, 10°C, 15°C and 35°C. Quantitative analysis was carried out using high performance liquid chromatography. The diffusion coefficients for each parameter were evaluated and these demonstrated that at the low salinity the release was approximately 4 times faster than at the higher salinity. At both salinities increasing the temperature increased the diffusion coefficient. It is thought that salinity influences the diffusion coefficient and the passage of BAC through the pores within the hydrogel by its effect on the degree of micelle formation.