Fig. -1 Coacervation on the dilution of model shampoo. (Left) The lower phase is coacervate deposited from model shampoo on dilu tion with water follo

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Fig. -1 Coacervation on the dilution of model shampoo. (Left) The lower phase is coacervate deposited from model shampoo on dilu tion with water followed by centrifugation (60000rpm, 2h) at 40 Ž. (Right) The coacervate merely flows due to its high viscosity.

Table-1 Properties of cationic polymers. * per unit of glucose. ** Cationic potato starch has the same content of nitrogen atom (N) as CC 0.35. Table-2 Formula of model shampoo. J. Soc. Cosmet. Chem. Japan Vol.38, No. 3 2004 213

Fig. -2 Evaluation of model shampoo. CC 0.05 ( œ), CC 0.22( ), CC 0.35 ( ), CC 0.45 ( ), CPS ( Ÿ). Each grade corresponds to excellent (5), good (4), standard (3), poor (2), bad (1), respectively.

Fig. -3 Turbidity measurements of shampoo at various relative concentrations. The symbols correspond to CC 0.05 ( œ), CC 0.22 ( ), CC 0.35 ( ), and CC 0.45 ( ) in Fig.- 3- (1), CC 0.35 ( ) and CPS ( Ÿ) in Fig.-3- (2), respectively. Fig. -4 Weight percentage of coacervate for model shampoo at a relative concentration (0.14). As shampoo containing CC 0.05 doesn't exhibit coacervation, symbol (*) in figure means a baseline in this experimental method. J. Soc. Cosmet. Chem. Japan Vol. 38, No.3 2004 215

Fig. -5 Plots of storage modulus (G') and loss modulus (G'') as a function of angular frequency for coac ervate. Closed symbols and open symbols denote G' and G'', respectively. The symbols correspond to CC 0.22 (, ), CC 0.35 ( œ, ), CC 0.45 (, ), respectively. Fig.-6 Adhesion amount of coacervate on the surface of damaged hair (N=3). Amount of adhesion is calculated from Eq. (3).

Fig. -7 AFM images of the surface of damaged hair after shampoo. Fig. -8 Fluorescence microphotograph of hair surface using FITC-CC 0.35 (left) and FITC-CPS (right).

1) E. D. Goddard, R. B. Hannan, J. Am. Oil Chem. Soc., 54, 561-566 (1977) 2) K. Ohbu, O. Hiraishi, I. Kashiwa, J. Am. Oil Chem. Soc., 59, 108-112 (1982) 3) P. L. Dubin, J. H. Gruber, J. Xia, H. J. Zhang, Col loid Interface Sci., 148, 35-41 (1992) 4) K. Yoshida, Y. Morishima, P. L. Dubin, M. Mi zusaki, Macromolecules, 30, 6208-6214 (1997) 5) Y. Wang, K. Kimura, P. L. Dubin, W. Jaeger, Mac romolecules, 33, 3324-3331 (2000) 6) Y. Li, P. L. Dubin, In Structure and Flow in Sur fanctant Solutions, edited by C. A. Herb, R. K. Prud'homme, ACS Symposium Series 578, Ameri can Chemical Society, Washington, DC, 1994, Chapter 23, p. 320-336 7) K. Talberg, B. Lindman, G. J. Karlstrom, J. Phys. Chem., 94, 4289-4295 (1990) 8) A. N. de Belder, K. Granath, Carbohydr. Res., 30, 375-378 (1973) 9) R. Nagarajan, B. Kalpakci, Polym. Prep. Am. Chem. Soc. Div. Polym. Chem., 23, 41-43 (1982)

Polyelectrolyte-Micelle Coacervation -Effect of Coacervate on the Properties of Shampoo- * Yoshiko Hiwatari**, Katsunori Yoshida**, Takahiro Akutsu***, Momo Yabu***, Shigeru Iwai*** Material Science Research Center, Basic Research Division**, Haircare Product Development Center, Product Development Division***, SHISEIDO Research Center (Shin-Yokohama) A typical formula for shampoo containing cationic polymers and anionic/amphoteric surfactants exhibits liq uid-liquid phase separation under certain conditions when the shampoo is diluted with water upon the actual use in bathroom. The lower dense phase is considered to be an insoluble complex formed with the cationic polymer and mixed surfactants. Generally, this associative liquid-liquid phase separation is called "coacerva tion" and the phase of complex is called "coacervate." Although it is well known that the usage texture of shampoo is influenced by coacervate, there are only a few reports about their relationship. In this work, we studied the properties of coacervate and its effect on the usage texture of shampoo, particularly focusing on the effect of the cationic polymer structure. We prepared five different model shampoos that contain various cat ionic polymers, and studied the effect of the characteristics of the polymers on the condition of the complex formations, the amount of coacervate, the rheological properties and the adhesive behavior of coacervate on the surface of damaged hair. It was found that both the structure and the degree of substitution of cationic polymer drastically changed the condition of coacervation. Moreover, the cationic polymers showed remarkable effect on the rheological properties and the adhesive behavior of the coacervate on the damaged hair. These results im plied that we could control the usage texture of shampoo by choosing proper cationic polymers to control coac ervation. Key words: coacervation, polyelectrolyte, cationic polymer, anionic/amphoteric surfactants, shampoo, elec trostatic interaction, liquid-liquid phase separation, rheological properties, AFM, FITC labeled polymer J. Soc. Cosmet. Chem. Japan Vol. 38, No. 3 2004 219