Hair conditioning technology without silicone

Abstract: To formulate natural oil based hair conditioners capable of delivering excellent conditioning benefits, a fundamental understanding of human hair surface at various degrees of chemical and mechanical damage is required, which underpins the deposition and lubrication mechanisms of oils on hair surface. Atomic force microscopy (AFM) was deployed to characterize the morphology and surface interactions [Labarre et al. Int. J. Cosmetic Sci. in press] of Caucasian hair over three regions along the fibre length (root, middle, and tip), on three levels of bleaching (virgin, low lift, and platinum). Increasing the physical wear and chemical treatment experienced by fibres damaged hair cuticle structure, with the combined damage resulting in stripping of cuticle structure. Highly damaged samples result in great surface adhesion under ambient conditions, suggesting a higher surface energy which leads to difficult combing and must be overcome by targeted oil deposition. The lubrication characteristics of thin silicone oil films (5 - 500 nm) of varying viscosity and surface tension was investigated using a customised tribological apparatus. We found that the dynamic coefficient of friction (CoF) decreases logarithmically with an increasing film thickness, suggesting that adequate oil thicknesses ( < 200 nm) could provide effective lubrication. Below 1000 cSt, more viscous oils showed better lubrication. However, the CoF increased with 10000 cSt oil due to a significant viscous force. A linear regression model was developed to identify the optimum oil viscosity and film thickness for providing maximum lubrication.