The role of polymer-surfactant interactions in the adsorption process of hair-conditioning polymers

Hair-conditioning polymers are in most cases cationic. Their adsorption to the negatively charged hair surface is strongly affected by their interaction with the anionic surfactants, which are also present in modern "2-in-1" shampoos. Almost 20 years ago, Goddard proposed that the adsorption process takes place, when the shampoo is washed off the hair [1]. Upon dilution a phase boundary is crossed and the polymer-surfactant complex precipitates on the hair surface. Since then, no systematic investigations on the adsorption process of conditioning polymers have been published. We reinvestigated this model employing a variety of physicochemical methods: turbidity, surface tension and surface rheology, AFM were used to characterise the polymer/surfactant complex of two polymers (polyquaternium) and an anionic surfactant (Texapon(R) NSO).