Salinity and temperature effects on the release of benzalkonium chloride from hydrogel material

The effects of salinity and temperature on the release of the quaternary am monium compound, benzalkonium chloride (BAC), from a poly (2-hydroxyethyl m ethacrylate) (PHEMA) hydrogel were studied. Previous research had shown tha t such a combination produced a transparent coating, which demonstrated red uced biofouling properties in a marine environment. Release was monitored a t two salinities, low (4 parts per thousand) and normal (35 ppt) which is t he approximate salinity of natural seawater, as well as at four temperature s 5 degrees C, 10 degrees C, 15 degrees C and 35 degrees C. Quantitative an alysis was carried out using high performance liquid chromatography. The di ffusion coefficients for each parameter were evaluated and these demonstrat ed that at the low salinity the release was approximately 4 times faster th an at the higher salinity. At both salinities increasing the temperature in creased the diffusion coefficient. It is thought that salinity influences t he diffusion coefficient and the passage of BAC through the pores within th e hydrogel by its effect on the degree of micelle formation.