JOURNAL OF COSMETIC SCIENCE 38 CONCLUSIONS The model calculations show, in agreement with practical observations, that the relative humidity of the environment as well as hair damage have an important infl uence on the performance of a non-permanent hairstyle on the basis of water waving. However, irre- spective of the environmental conditions, as long as they stay below the glass transition, it is nevertheless the phenomenon of physical aging that makes water waving a feasible and practically successful process for hair styling. REFERENCES (1) F.-J. Wortmann, M. Stapels, and L. Chandra, Humidity dependent bending recovery and relaxation of human hair, J. Appl. Polym. Sci., 113, 3336–3344 (2009). (2) M. Feughelman, Mechanical Properties and Structure of Alpha-Keratin Fibers (University of New South Wales Press, Sydney, Australia, 1997). (3) D.A.D. Parry and P. Steinert, Intermediate fi laments: Molecular architecture, assembly, dynamics and polymorphism, Quarterly Rev. Biophys., 32, 99–187 (1999). (4) H. Zahn, F.J. Wortmann, G. Wortmann, K. Schaefer, R. Hoffmann, and R. Finch, “Wool,” in Ullmann’s Encyclopedia of Industrial Chemistry, 6th ed. (Wiley-VCH, Weinheim, Germany, 2003), Vol.39. (5) F.J. Wortmann, B.J. Rigby, and D.G. Phillips, Glass transition temperature of wool as a function of regain, Text. Res. J., 54, 6–8 (1984). (6) F.J. Wortmann, M. Stapels, R. Elliott, and L. Chandra, The effect of water on the glass transition of human hair, Biopolymers, 81, 371–375 (2006). (7) B.M. Chapman, The aging of wool. Part I: Aging at various temperatures, J. Text. Inst., 66, 339–342 (1975). (8) F.J. Wortmann and S. DeJong, Analysis of the humidity-time superposition for wool fi bers, Text. Res. J., 55, 750–756 (1985). (9) F.-J. Wortmann and I. Souren, Extensional properties of human hair and permwaving performance, J. Soc. Cosmet. Chem., 38, 125–140 (1987). (10) F.-J. Wortmann and N. Kure, Bending relaxation properties of human hair and permwaving perfor- mance, J. Soc. Cosmet. Chem., 41, 123–139 (1990). (11) B.M. Chapman, The rheological behaviour of keratin during the aging process, Rheol. Acta, 14, 466– 470 (1975). (12) E.F. Denby, A note on the interconversion of creep, relaxation and recovery, Rheol. Acta, 14, 591–593 (1975). (13) J.D. Ferry, Viscoelastic Properties of Polymers ( John Wiley & Sons New York, 1980). (14) L.C.E. Struik, Physical Aging in Amorphous Polymers and Other Materials (Elsevier, Amsterdam, 1978), Chapter 4. (15) F.J. Wortmann, The viscoelastic properties of wool and the infl uence of some specifi c plasticizers, Colloid Polym. Sci., 265, 126–133 (1987). (16) C.A. Angell, K.L. Ngai, G.B. McKenna, P.F. McMillan, and S.W. Martin, Relaxation in glassforming liquids and amorphous solids, J Appl. Phys., 88, 3113–3157 (2000). (17) J.W.S. Hearle, B.M. Chapman, and G.S. Senior, The interpretation of the mechanical properties of wool, Appl. Polym. Symp., 18, 775–794 (1971). (18) M. Feughelman and M. Druhala, The lateral mechanical properties of alpha-keratin, Proc. 5th Int. Wool Text. Res. Conf. Aachen, II, 340–349 (1976). (19) F.J. Wortmann, A. Hullmann, and C. Popescu, Water management of human hair, IFSCC Mag., 10, 317–320 (2007). (20) B.M. Chapman, Linear superposition of time-variant viscoelastic responses, J. Phys. D: Appl. Phys., 7, L185–L188 (1974). (21) F.-J. Wortmann, C. Popescu, and G. Sendelbach, Nonisothermal denaturation kinetics of human hair and the effects of oxidation, Biopolymers, 83, 630–635 (2006). (22) F.J. Wortmann, C. Popescu, and G. Sendelbach, Effects of reduction on the denaturation kinetics of human hair, Biopolymers, 89, 600–605 (2008).

J. Cosmet. Sci., 61, 39–48 ( January/February 2010) 39 Polyoxyethylene/polyoxypropylen dimethyl ether (EPDME) improves the structure of intercellular lipids in SDS-induced dry skin EIICHIRO YAGI, TAKASHI OHMORI, and KAZUTAMI SAKAMOTO Shiseido Research Center, 2-2-1 Hayabuchi, Tsuzuki-ku, Yokohama, 224-8558 (E.Y., T.O.), and Tokyo University of Science, Department of Pure and Applied Chemistry, Faculty of Science and Technology, 2641 Yamazaki, Noda, Chiba, 278-8510 (K.S.), Japan. Accepted for publication July 7, 2009. Synopsis The dimethyl ether of an amphiphilic random ethylene oxide/propylene oxide copolymer (EPDME) is useful for the preparation of fi nely dispersed micro-emulsions. We examined whether EPDME is effective for skin moisturization by means of electron paramagnetic resonance (EPR) studies of ex vivo specimens of stratum corneum (SC) obtained by successive stripping. The values of the order parameter S obtained by EPR mea- surement indicated that EPDME treatment improved sodium dodecyl sulfate (SDS)-induced disruption of SC lipid structures. This effect appeared to be related to improved hydration of the epidermis, not occlusion by EPDME, since there was no signifi cant change in transepidermal water loss (TEWL). INTRODUCTION Development of novel functional molecules for improved cosmetic or pharmaceutical formulations that have a physiological effect on skin is an important task for cosmetic scientists. We have developed a random copolymer, polyoxyethylene/polyoxypropylen dimethyl ether (EPDME) as a functional amphiphilic polymer suitable for the prepara- tion of fi nely dispersed micro-emulsions. EPDME was found to be very effective for skin moisturization to protect dry skin or to improve poor skin conditions (1). When EPDME is combined with glycerin in a formulation, EPDME increases the amount of glycerin held in the SC (1). There are many empirical data indicating that EPDME is effective in cosmetics for people with sensitive skin. The objective of this study is to elucidate the mechanism of EPDME’s effect on the skin condition, by means of an electron paramag- netic resonance (EPR) analysis of lipid structure in successively stripped SC layers, along with measurements of SC hydration and of transepidermal water loss (TEWL) from the skin, with or without SDS treatment. Address all correspondence to Eiichiro Yagi.