284 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS conditions are given in Table III. The nondispersion or polar contribution '),.•t' in the advancing mode is small compared to the dispersion contribution 'y.•. In the "equilib- rium" condition, when the fiber is left in the liquid for -15 rain, it is seen that 3,.• t' increases considerably and 'ys • decreases slightly, thus leading to a net increase in the total surface free energy. The increase seems to be due to the interaction of hair and water leading to hydrogen bond breaking and consequent orientation of the macromolecules in the surface regions, as was suggested earlier. ACKNOWLEDGMENT The work reported here was conducted as part of a project on "Studies of the Modifica- tion of Human Hair Properties by Surface Treatments" sponsored by a group of corpo- rate Textile Research Institute participants. REFERENCES (1) N. L. R. King and J. H. Bradbury, The chemical composition of wool. Part V, The Epicut•cle, Aust. J B/o/. Sci., 21,375 (1968). (2) L J. Wolfram and M. K. O. Lindemann, Some observations on the hair cuticle, J. Sot', Cosmet. Chem., 22,839-50 (•971). (3) J. A. Swift and B Bews, The chemistry of human hair cuticle. Part I: A new method for the physical isolation of cuticle, J. Sot'. Cosmet. Chem, 25, 13-22 (1.974). (4) E.G. Shafrin and W. A. Zisman, Constitunve relations in the wetting of low energy surfaces and the theory of the retraction method of preparing monolayers, J. Phys. Chem., 64, 519-24 (1.960). (5) B. Miller and R. A. Young, Methodology for studying the wettability of filaments, Text. Re•. J.. 45, 359-65(1.975). (6) F. M. Fowkes, Determination of interfacial tensions, contact angles, and dispersmn forces in surfaces by assuming ad&tivity of intermolecular interactions in surfaces, J. Phys. Chem., 66• 382 (1962). (7) S. Wu, Calculatmn of interfacial tension in polymer systems, J. PoIym. Sci., Part C, 34, 19 (1.971). (8) H. A. Shuyten, J. W. Weaver, andJ. D. Reid, An index of the water-repellancy of textiles from the sur- face tension of aqueous solutions,Amer Dye.•t. Rep.. 38,364-8 (1949). (9) Y. K. Kamath, C. J. Dansizer, and H.-D., We•gmann, Wettabihty, contact angle and wetting hysteresis ofkeratin fiber surfaces, unpublished communication. (1.0) E G. Shafrin and W. A. Zisman, Effect of adsorbed water on the spreading of organic liquids on soda- lime glass, J. Amer. Chem. Sot', 50,478-84 (1967). (1.1) W. E. Savige and J. A MacLaren, Oxidanon of disulfides with special reference to cystine, in N. Kharasch and C. Meyers, Eds., The Chemistry of Organic Sulfur Compounds. vol. 2, Pergamon Press, New York, 1.966, pp. 367-402. (1.2) P. Alexander and R. F. Hudson, Wool, •ts Chemistry a•d Physics, Franklin Publishing Co., New Jersey, 1.963, Pp. 262-64. (13) A. E1-Shimi and E. D. Goddard, Wettability of some low energy surfaces. Part I. Air/liquid/solid inter- face, J. Colloid Interfat. Sci., 48,242-8 (1974). (14) H. D. Feldtman and J. R. McPhee, Spreadi•tg and Adhesion of Polymers on Wool. Text. Res. J,, 34,634-42 (1.964). (15) H• Alter and H. Cook, The effect of adsorbed water on the critical surface tension of hair, J. Colloid In- terfac, Sc•., 29,439-43 (1.969). (16) J. R. Dann, Forces involved in the adhesive process, J. Colloid Interfat. Sci., 32,302-20 (1970).

J. Soc. Cosmet. Chem., 28, 285-314 (May 1977) Studies of water-in-oil (w/o) emulsion stabilized with amino acids or their salts YOSHIMARU KUMANO, SHIN NAKAMURA, SADAAKI TAHARA, and SABURO OHTAShiseido Laboratories, 1050, N•pacho, Kohokuku, Yokohama,Japan, Received June 15, 1976. Presented Ninth IFSCC Congress,June 1976, Boston, MA. Synopsis WATER-IN-OIL (W/O) EMULSIONS STABILIZED by using gels formed between surfactants and aqueous solutions of AMINO ACIDS were studied The gel can only be obtained with a fluid surfactant which has lipophilic properties and a specific orderly lameliar structure and amino acids or their salts which are readily soluble in water. By dispersing these gels into the oil phase and then adding the water phase, extremely stable w/o emulsions with wide ranges of water content were obtained. This type of emulsification was termed the "gel-emulsifica- tion method" by the authors. When this new technology was applied to the preparation of cosmetics, products with outstanding characteristics were obtained. The function of the amino acids in the emulsification were investigated by using physico-chemical methods such as X-ray analysis, nuclear magnetic resonance (NMR), heat of solution, electron microscopy (EM), and measurement of the water content solubilized in the surfactant phase. It may be concluded that the amino acids are effective in forming a tight surface atmosphere around the water particles and in preventing coa- lescence of water particles by strong hydration effect of the amino acids, thus stabilizing the w/o emulsion. INTRODUCTION Generally, w/o emulsions are said to be much more advantageous to human skin than an oil-in-water (o/w) emulsion. Gattefosse et al. (1,2) described the mechanism of ap- plication ofw/o emulsions to the skin as follows. The continuous fatty layer, in which minute droplets of water are distributed, is in contact with the epidermis and facilitates adhesion. After the water evaporates, the residual fatty phase of the emulsion on the skin is elastic and resistive, protecting the deeper layers of skin from dehydration and exaggerated hydration. Furthermore, other scientists (3) have also dealt on the properties of w/o emulsions of spreading well onto stratum comeurn and aid in the prevention of chemical and natural attacks thereon, retarding moisture loss, which in turn helps to maintain flexibility. 285