Differential behavior of sodium laurylsulfate micelles in the presence of nonionic polymers

HYPOTHESIS

Theory and practice have proven that the cleansing properties and irritation potential of surfactants can be controlled with the addition of co-surfactants or polymers. The size of the surfactant-polymer nanoassembly, which differs from the pure surfactant micelle, has been postulated to be the cause of the differences in a surfactant system's ability to disrupt the skin barrier. However, a firm structure-function relationship connecting polymer and surfactant under a consumer relevant condition is yet to be established. It is therefore hypothesized that apart from the size, the shape and the chemical nature of the polymer might play crucial roles.

EXPERIMENTS

We used combined small-angle neutron scattering, nuclear magnetic resonance spectroscopy, tensiometry, and dye solubilization methods to investigate the shape, size, and intermolecular interactions involved in sodium laurylsulfate-based systems in the presence of two industrially important and chemically distinct polymers, polyethylene glycol and polyvinyl alcohol, adopting a consumer relevant protocol.

FINDINGS

Apart from size, shape and inter-micellar interactions fine-tuned by the presence of the polymers are found to be the important factors. Secondly, the physicochemical property of the polymer including chemical structure, conformation, hydrophilicity, presence of side groups, all can have crucial influence on polymer-surfactant interaction, micelle formation, and micelle stability.