Cuticular damage to African–American hair during relaxer treatments – A microfluorometric and SEM Study

Abstract

Citation: IFSCC Magazine, 11 (2008) (2) 131–137Abstract: In earlier publications [1,2,3 we discussed several in‐depth studies of characterization and quantification of damage done to European dark brown hair fibres by photochemical and cosmetic‐chemical oxidation (bleaching) and reduction (perming) processes. These earlier studies established considerable changes in surface chemistry such as an increase in acidity and hydrophilicity. We discussed in detail the breakdown of the lipid domains (delipidation) of the outer ®‐layer of the exposed scale faces and generation of anionic (sulphonic acid) groups (acidification) on the hair surface caused by these oxidative and reduction processes. The goal of this current study is to characterize and quantify the level of chemical and physical changes in the surface of African–American hair caused by various »lye‐based« and »no‐lye« relaxer treatments [4]. This study attempts to establish which product delivers the best »hair straightening« performance while resulting in the least chemical and physical changes in the hair surface. We again use a microfluorometric technique with the help of the cationic fluorochrome Rhodamine B to detect, map and quantify relaxer‐induced changes in the surface chemistry of human hair fibre. In addition, we also use SEM at various magnifications to highlight relaxer‐induced changes in the physical nature of the hair surface. We attempt to associate the level of increase in fluorescence intensity, which represents an increased level of delipidation/acidification of the hair surface, with the damage level to the hair topography, and thus, determine the least damaging cosmetic chemical process. Damage to the physical nature of the hair topography as observed by SEM shows a clear difference between treatments involving lab‐made relaxer solutions and commercial relaxer systems.Keywords: African‐American hair, commercial relaxer systems, microfluorometry, relaxer‐induced surface changes/damage, physical nature, surface chemistry, relaxer solutions, SEM, +lye‐based1/2 and +no‐lye1/2 relaxers,