SILICONE-QUAT INTERACTIONS 141 performances, the dry combing improvement being noticeably superior to the wet combing effects (based on %ACL reduction). Low-molecular-weight silicones (fluids). The data points are a lot more scattered for mem- bers of this class, especially for fluid 1. As shown in Figure 4 (A for fluid 1, B for fluid 2, and C for fluid 3), there does not appear to be much of a difference between dry combing and wet combing improvement. The %ACL reductions of the three treatments were in the 35%-60% range for both wet and dry combing. The same trend (of improved performance for low amounts of silicone deposited followed by leveling off) is seen with these lower molecular weight polydimethylsiloxanes (LMWS). Our lowest data point (for fluids 2 and 3) in this case is around 55 •g silicone/g hair, so that the minimum amount of silicone required for the improved performance and the threshold level at which the improvement levels off is now between 0-55 •g silicone/g hair. Comparison between HMWS and LMWS. As Figure 5A shows, the HMWS display dry combing performance superior to that of the LMWS. This is in good correlation with a study where the •k value of dry hair fibers was measured as a function of the molecular weight (Mw) of the PDMS depositing on the hair (15). It was found that the coefficient decreased (i.e., improved lubricity) as the molecular weight of the silicone increased, provided that the Mw was greater than 20,000. e• 60 •- 40 100 100 - • , ,0 A ' o'o 0 250 500 750 1 0 1250 Amount Silicon Deposited (gg Si/g hair) 80- 60- 40- 20- o 0 250 o B 500 750 1 0 1250 Amount Silicon Deposited (gg Si/g hair) 100 • 60 0 •. 40 Ool I I i J0 0 250 500 750 1 0 1250 Amount Silicon Deposited (gg Si/g hair) Figure 4. Dry ( ¸ ) and wet (O) combing performance of fluid 1 (A), fluid 2 (B), and fluid 3 (C) in absence of the quat.

142 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS lOO ß 60- O O 40 2O o,• ß O A I i i i 250 500 750 1000 12 0 80- 40- O ß ß 250 ß øøß O ß •, OO O B I I 500 750 1000 1250 Amount Silicon Deposited (gg Si/g hair) Amount Silicon Deposited (gg Si/g hair) Figure 5. Dry (A) and wet (B) combing performance of all the fluids ( 0 ) and gums/blend (O) in absence of the quat. There is no significant difference between the HMWS and LMWS as pertaining to wet combing improvement. They both reduce the average combing load by about 35%- 50%, as shown in Figure 5B. EFFECT OF SILICONE ON COMBING PERFORMANCE IN PRESENCE OF THE QUAT Again, both wet and dry combing performances were assessed for the different levels of the treatments used. In addition, tresses treated only with the quat were combed for comparison purposes. High-molecular-weight silicones (gums and the gum blend). The %ACL reductions of the three treatments (gums 1 & 2 and blend) were in the 87%-94% range for wet combing and in the 56%-87% range for dry combing. The same trends of initial rapid increase followed by a gradual leveling off in combing performance improvement is valid for the experiments in the presence of the quat, as shown in Figure 6 (A for gum 1, B for gum 2, and C for blend). Low-molecular-weight silicones (fluids). The %ACL reductions of the three treatments were in the 73%-91% range for wet combing and in the 47%-79% range for dry combing. The same trend (of improved performance for low amounts of silicone deposited, fol- lowed by leveling off) is seen with these lower molecular weight polydimethylsiloxanes (LMWS), as shown in Figure 7 (A for fluid 1, B for fluid 2, and C for fluid 3). Comparison between HMWS and LMWS. As in the case of the experiments involving the absence of the quat, HMWS show better dry combing benefits when compared to the LMWS (see Figure 8A). They may also have a slight edge when considering wet combing benefits (see Figure 8B). Comparison between wet combing in the absence andpresence of the quat. The quat by itself was not effective in reducing the wet combing load (%ACL•e d = 3%). The silicones did a much better job, however there was a dramatic improvement in the wet combing