The effect of counterions of linear alkylbenzene sulfonate on skin compatibility.

Abstract

Interactions of a widely used commercial anionic surfactant, linear alkylbenzene sulfonate, with zein protein, a water insoluble protein, was studied to better understand the effects of the counterion on skin irritation of anionic surfactants. The neutralizing ions used were inorganics: Li+, Na+, K+, Mg2+, and NH4+ and organics: monoethanolamine, diethanolamine, and triethanolamine. According to the results obtained, the influence of counterions of anionic surfactants on zein solubilization is significant; with magnesium counterions showing lower zein solubilization. In aqueous solutions, zein solubilization by anionic surfactant is related to the effect of the counterion on the critical micelle concentration of the surfactant for the inorganic counter-ions; for the organic counter-ions, effects of tighter anionic binding in the micelle also contribute to zein solubilization trends.