2005 ANNUAL SCIENTIFIC MEETING 179 Silicone deposition on hair - The total amount of silicone deposited on hair was measured on hair that was treated five times with the prototype formulation listed in Table I. The hair was rinsed and dried between each treatment. Two types of undamaged hair, European brown hair and Asian hair, and one type of damaged hair, commercial bleached hair (all from International Hair Importers and Products Inc.), were used for this study. The silicone was extracted from the hair by a 50/50 (v/v) methyl butyl ketone/ toluene solution, and then measured using atomic absorption spectrophotometry. The results using both surfactant "A" and "B" showed that the structure of the cationic HEC - especially the molecular weight - the silicone droplet size and type of hair all had a very strong impact on silicone deposition. In Figure 1, the formulation containing small silicone particle size (0.5µm) without cationic HEC, such as Formula E-1 gave very poor silicone deposition on all types of hair. However, the formulation containing cationic HEC improved the silicone deposition. For example, the cationic HEC with high molecular weight (HL in Formula E-V), delivered more silicone than the low molecular weight polymer (LH in Formula E-III). The hydrophobically modified cationic HEC, PQ-67, deposited even more silicone on the hair, especially damaged, commercial bleached hair. This trend was reversed with the formulations containing large particle size silicone. Figure 1: Deposition of Small Silicone Particle from Surfactant A in Different Types of Hair 300 250 � • % 200 i 150 g100 in 50 E-1 E-111 E-VE-VII E-IX E-1 E-111 E-V E-IX E-1 E-111 E-V E-IX European Brown Hair Commercial Bleached Hair Asian Hair Figure 2: Deposition of Large Silicone Particles from Surfactant A on Different Types of Hair 3500 3000 � 2500 �2000 � 1500 '::° 1000 ci"i 500 - E-11 ' E-IV E-VI E-VIII E-X E-11 E-VI E-VIII E-X E-11 E-VI E-VIII E-X European Bra'Ml Hair Commerc,al Bleached Hall As,an Hair In Figures 2 and 3 the formulations containing large silicone particle size (20µm) without cationic HEC (Formulas E-II and A-II) yield very high silicone deposition on undamaged hair, such as European brown hair and Asian hair. This phenomenon can be explained by the fact that the attractive Van der Waals forces between particles increase with particle size and, eventually, the large particles tend to adhere better when they collide with another surface (6). However, the silicone deposition measurement shows a big variation of silicone deposition on different hair tresses. This indicates the deposition is uncontrollable and could lead to inconsistent conditioning and eventual silicone build-up. Conversely, the formulation containing cationic HEC yields more consistent and controlled deposition. The data also suggests that when large particle size silicone is used, low molecular weight cationic HEC should be used to maximize deposition onto undamaged hair. This difference in deposition profile may be due to high molecular weight polymers stabilizing the large silicone droplets and preventing them from colliding with the hair surface. The large particle size silicone, however, is relatively easier to deposit onto undamaged, European brown, hair than damaged, commercial bleached, hair regardless of which polymer is used. The bleaching process has significantly modified the hair surface of the commercial bleached hair to a highly negatively charged surface which potentially affects the silicone deposition process. The silicone deposition from the formulation of Surfactant B containing large silicone particles shows a similar trend as the formulation from Surfactant "A" (Figure 2 & 3). However, the relative amount of silicone deposited onto European brown hair from surfactant "B" is much lower than surfactant "A". This demonstrates that the surfactant system can significantly change the silicone deposition process.

180 JOURNAL OF COSMETIC SCIENCE Figure 3: Silicone deposition on European Brown Hair Figure 4: Summary of Silicone Deposition {Large Silicone Particle Size) from Surfactant B Silicone Particle Size vs Pol mer MW 400 350 � 300 � 250 E i 200 g' 150 en 100 50 Large Particle Size Small Particle Size A-II A-Ill A-PJ A-VI Cationic HEC Molecular Weight The above data suggests that the silicone deposition from silicone containing shampoos onto the hair is a very complex process. Many factors, such as silicone droplet size, cationic polymers, surfactant system and hair type can change the deposition process. The general trend of silicone deposition with different silicone particle sizes and different cationic HEC polymer molecular weight is summarized in Figure 4. In general, more large particle size silicone is deposited by low molecular weight HEC, while more small particle size silicone is deposited by high molecular weight HEC. One of the major roles of cationic HEC in a conditioning shampoo is to control the silicone deposition in order to maintain good overall conditioning performance. Thus, fonnulators need to select the right combination of silicone particle size with the structure of cationic HEC in order to deliver the desired amount of silicone onto the hair. Conclusion: This study demonstrates the importance matching the optimum silicone particle size and cationic polymers structure in order to deliver the desired amount of silicone onto a specific type of hair in a predictable way to maximize the conditioning shampoo perfonnance without causing a silicone buildup issue. References: (/) (2) (3) (4) (5) (6) (7) M.D. Berthiaume, "Silicones in Cosmetics," in Principles of Polymers Science and Technology in Cosmetics and Personal Care, E.D, Goddard and J.V. Gruber, Eds (MarcelDekker, New York, 1999), pp. 275-324. J. Jachowicz and M.D. Berthiaume, "Heterocoagulation of Silicone Emulsions on Kerstin Fibers", Journal of Colloid and Interface Science, Vol. 133, No. I, Nov. 1989, pp. 118-134. M.D. Berthiaume and J. Jachowicz, "The Effect of Emulsifiers and Oil Viscosity on Deposition of Nonionic Silicone Oils from Oil-in-Water Emulsions into Kerstin Fibers", Journal of Colloid and Interface Science, Vol. 141, No.2, Feb. 1991, pp. 299-315. E.D. Goddard, "Measuring and Interpretation Polycation Adsorption," in Principles of Polymers Science and Technology in Cosmetics and Personal Care, E.D, Goddard and J.Y. Gruber, Eds (MarcelDekker, New York, 1999), pp. 465-508. J.V. Grubber, B.R. Lamoureux, N. Joshi, and L. Moral, "The use of X-ray Fluorescent Spectroscopy to Study the Influences of Cationic Polymers on Silicone Oil Deposition from Shampoo", J. Cosmet. Sci., 52, pp. 131-136. R.Y. Lockhead, Conditioning Shampoo, Soap/Cosmetics/Chemical Specialties, PP 42-49, October /992 M. Gamez-Garcia, Polycation Substantivity to Hair, IFSCC, Vol. 4, PP 99-107 (200/)