SCC Annual Scientific Meeting and Technology Showcase Report

By: Katie Schaefer

Posted: December 16, 2008

page 9 of 12

Polymer/Surfactant Delivery Systems for Personal Care

Day two of the meetings kicked off with introductions by Wil Hemker, of the University of Akron Research Foundation, of speakers for the morning session tribute to Des Goddard. Topics in the first session ranged from advances in surfactant interactions with proteins and polymer-surfactant interactions, to the modeling of polycation surfactant complexes in shampoos with deposition properties and polymer-surfactant association for improved tissue compatibility.

Surfactant interactions with proteins and SC: K.P. Ananthapadmanabhan (Ananth), PhD, of Unilever in Trumbull, discussed the interaction of surfactants with proteins, which has been a topic of interest over the past several decades. According to Ananth, it is well-known that surfactants interact strongly with the stratum corneum (SC) proteins, leading to their swelling and denaturation, and that they have high potential to cause irritation, erythema and itch. This reaction occurs via a “series of events that lead to increasing pore size.” He noted that the tendency of surfactants to interact with proteins follows the order: anionic surfactants > amphoteric surfactants > nonionic surfactants.

His recent work shows that protein denaturation potential of surfactants scales with micelle charge density, and that this correlation has been found for a range of surfactants and surfactant mixtures. Thus, micellar charge density provides an “irritation ruler” and can allow for the prediction of skin irritation potential of surfactants.

Fine-tuning polymer/surfactant interactions: Following Ananth, Susan Jordan, PhD, of Dow Chemical, honored Des before beginning her discussion on polymer-surfactant interactions. “Over thirty years, Des Goddard introduced state-of-the-art methodologies to the personal care industry.” She referenced techniques he introduced, such as: streaming potential, atomic force microscopy (AFM), radio-labeled polymers and scanning electron microscopy (SEM). “Since [his] work … additional scientific approaches have been introduced including wet comb analysis, silicone deposition quantitation, fluorescence labeling, polymer dye techniques, head space analysis and spin coating.” Jordan added that new and novel polymers have been developed using these techniques to improve product performance.