The effect of emulsifiers and oil viscosity on deposition of nonionic silicone oils from oil-in-water emulsions onto keratin fibers

Abstract

The effect of oil viscosity, as well as the type and concentration of emulsifiers, on the deposition of nonionic silicone oils from oil-in-water emulsions on both untreated and cationically modified human hair was investigated. The emulsifiers in the ionic emulsions consisted of a mixture of either sodium octadecyl sulfate (SODS) or cetyltrimethylammonium bromide (CTAB) in conjuction with the two nonionic, ethoxylated nonylphenol surfactants employed in neutral emulsion systems. At constant oil viscosity, the rates of deposition were found to decrease with increasing nonionic surfactant concentration. At constant surfactant concentration, increasing oil viscosity gave rise to increasing rates and extent of deposition. Incorporation of ionic surfactants into the emulsifier systems results in corresponding changes in the zeta potentials of oil droplets, and consequently leads to shifts in the rates of deposition on untreated (negatively charged) or cationically modified keratin surfaces. The deposition data are discussed in relation to oil droplet size, zeta potential, and viscosity.