2010 TRI/PRINCETON CONFERENCE 175 On the other hand, an increase in the micelle charge does not seem to have a strong im- pact on the silicone deposition. Further analysis considers the interaction profi les shown in Figure 16. The profi les show a strong interaction between the cationic charge density of the cassia polymers and the micelle charge density. It is seen from this analysis that the average charge on the surfactants (micelle charge) is important in determing silicone de- position and, specifi cally, that a higher charge produces more deposition for the higher cationic charge cationic cassia polymer but less silicone deposition for the lower cationic charge cassia polymer. It is further seen in the main effects as well as the interactions that a higher aspect ratio decreases silicone deposition. The effect of the ratio of aspect ratio to micelle charge on the cationic deposition of either EX-906 or EX-1086 is reported in Figure 17. As observed for the silicone deposition, the ratio of the micelle aspect ratio and micelle charge has an effect on the cationic polymer deposition on wool. The amount of cationic polymer deposited on wool after 2 washes decreases as the aspect ratio to micelle charge ratio increases. Figure 15. Silicone deposition prediction for EX-906 and EX-1086. Figure 16. Interacion parameters for EX-906 and EX-1086.

JOURNAL OF COSMETIC SCIENCE 176 CONCLUSIONS The results clearly demonstrate that, contrary to what was previously assumed, the exten- sion of coacervation profi les to a higher dilution range for formulations containing a more highly charged cationic polymer does not lead to improved conditioning performance. Other factors besides the shape of the coacervation curve infl uence the conditioning per- formance of cationic cassia polymers on European brown hair. Even so, the formulation of the surfactant composition has a strong infl uence on the cationic polymer performance and the silicone deposition is a primary determinant of the conditioning sensory perfor- mance. Three parameters are proposed to be of importance in determining silicone and cationic polymer deposition: cationic cassia polymer charge density, average surfactant charge (micelle charge) and total amount of surfactant (aspect ratio). Sensory hair panel testing, silicone and cationic polymer deposition results can be predicted to a very high confi dence level using models that incorporate these three factors. There appear to be several mechanisms that are of importance in determining silicone deposition and, there- fore, sensory performance. Which of these is operative depends on the cationic polymer charge density. Silicone deposition data as well as sensory panel tests both indicate that for a more highly charged polymer, either the adhesion of the polymer-surfactant complex to the hair and/or its ability to fl occulate the silicone is the determining factor, whereas with a lower cationically charged polymer, the amount of complex formed is more important. ACKNOWLEDGMENTS The authors thank Lubrizol Advanced Materials, Inc. (a wholly owned subsidiary of The Lubrizol Corporation) for permission to publish and Denise Wade Rafferty and Daniel Hasman for their useful discussion of this work. REFERENCES (1) R. Y. Lochhead, Conditioning shampoo, Soap Cosmet. Chem. Spec., 42–49 (1992). (2) E. D. Goddard, “Polymer/Surfactant Interactions in Applied Systems,” in Principles of Polymer Science and Technology in Cosmetics and Personal Care, E. D. Goddard and J. V. Grubber, Eds. (Marcel Dekker, New York, 1999), pp. 181–215. (3) P. Hossel, R. Dieing, R. Norenberg, A. Pfau, and R. Sander, Conditioning polymers in today’s shampoo formulations—Effi ciency, mechanisms and tests methods, Int. J. Cosmet. Sci., 22(1), 1–10 (2000). Figure 17. Correlation of cationic deposition with the ratio of aspect ratio to micelle charge for EX-906 and EX-1086.