308 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS discussions. Y. Feng would like to thank the Lawrence M. Gelb Research Foundation for providing financial support. REFERENCES (1) C. R. Robbins, The Chemical and Physical Behavior of Human Hair (Van Nostrand Reinhold, New York, 1979). (2) J. F. Corbett,J. Chem. Soc., B, 1418-1427 (1970). (3) J. F. Corbett, J. Soc. Cosmet. Chem. 20, 253-263 (1969). (4) J. F. Corbett, J. Chem. Soc., B, 207-212 (1969). (5) J. F. Corbett, J. Chem. Soc., B, 818-822 (1969). (6) J. F. Corbett, J. Soc. Cosmet. Chem. 23, 683-692 (1972). (7) J. F. Corbett, JSDC, 71-73 (February 1969). (8) N. Pekmez, K. Pekmez, and A. Yildiz,J. Electroanal. Chem., 348, 389-398 (1993). (9) U. Nickel, Y. H. Chen, S. Schneidner, M. I. Silva, H. D. Burrows, and S. J. Formosinho, J. Phys. Chem., 98, 2883-2888 (1994).

j. Soc. Cosmet. Chem., 45, 309-336 (November/December 1994) Fingerprinting of cosmetic formulations by dynamic electrokinetic and permeability analysis. I. Shampoos j. JACHOWICZ* and C. WILLIAMS, Clairol Inc., 2 Blachley Road, Stamford, CT Received January 6, 1994. Synopsis The interaction of shampoos with human hair was studied by employing an instrument that can perform simultaneous analysis of electrokinetic parameters (streaming potential and conductivity) and the perme- ability of fiber plugs. The experimental protocol included the measurements of a newly formed hair plug and its treatment with a solution of a shampoo or a model compound, followed by rinsing with the test solution. Electrokinetic and permeability data collected during the rinsing stage allowed detailed analysis of the dynamics of change in the ionic character of hair surface produced by the adsorption of a conditioning agent. The variation in the thickness of surface deposits could be evaluated from the flow-rate measure- ments. Several types of formulations were analyzed, such as nonconditioning shampoos based on anionic surfactants, and conditioning systems containing cationic polymers, cationic surfactants, and silicone oils. It is shown that a combination of experimental traces, including streaming and zeta potentials, conduc- tivity, and flow rate (permeability) as a function of time, is unique for each investigated formulation. Multiple treatments with the same formulation were allowed to estimate the extent of buildup of condi- tioning layers. The ability of nonconditioning compositions to remove polymer and surfactant residues was analyzed by consecutive application of conditioning and nonconditioning formulations. INTRODUCTION Shampoos are complex mixtures of surfactants, oils, polymers, and preservatives. Their primary function is to clean hair by removing excessive amounts of sebum, residues of cosmetic treatments, and dust and grime accumulated from the air (1). There is a variety of commercial formulations with components selected from hundreds of surfactants, lather boosters, conditioning agents, thickeners, opacifiers, preservatives, and other ingredients (2). All these materials can interact with each other in a shampoo compo- sition, forming a variety of colloidal structures such as micelies, mixed micelies, poly- mer-surfactant complexes, surfactant-surfactant complexes, emulsions, lamellar phases, etc. Depending on the composition, the shampoos can clean or condition hair to various degrees by interacting with the soil on the fiber, as well as with the fiber itself, by adsorption/desorption of surfactants, polymers, and complexes, and by solubilization or deposition of oils. All these processes occur during lathering and rinsing of the treated hair by an excess of water. In this paper, we present the data demonstrating that a new * Present address: International Specialty Products, 1361 Alps Road, Wayne NJ 07470. 309