JOURNAL OF COSMETIC SCIENCE 134 Figure 5. Reductions in dry combing forces of conditioner-A treated hair. Figure 7. Reductions in dry combing forces of conditioner-B treated hair. Figure 6. Reductions in wet combing forces of conditioner-A treated hair.

2010 TRI/PRINCETON CONFERENCE 135 CORRELATION BETWEEN REDUCTION IN SURFACE ENERGY AND DECREASE IN COMBING FORCE Surface energy can be used as an indicator of surface reactivity. Higher the surface energy, more hydrophilic the hair surface, and stronger interactions between hair and water and between hair fi bers each other will be. These will generate larger combing forcers during combing processes. Therefore, it is of our interest to establish correlations between reduc- tion in surface energy and decrease in dry/wet combing forces of conditioner-treated hair samples. In this study, bleached and virgin hair were used and treated with conditioners A and B separately. Percentage changes in surface energy, dry combing forces, and wet combing forces on both bleached and virgin hair are plotted together in Figures 9 and 10, correspondingly, for conditioners A and B. It can be seen from Figure 9 that the average surface energy of conditioner-A treated vir- gin and bleached hair reduced about 30%, and corresponding dry and wet combing forces of treated hair tresses decreased about 70% and 90%, respectively. In Figure 10, the reduction in surface energy of conditioner-B treated bleached hair is 33.72%, which is more than the 27.64% for virgin hair. The decrease in dry combing forces for the bleached hair is 71.34%, which is much higher than the 34.96% for the virgin hair. The same trend is observed on reductions in wet combing forces between bleached and virgin hair. Figure 8. Reductions in wet combing forces of conditioner-B treated hair. Figure 9. Reduction of surface energy vs combing force for conditioner-A treated hair.