Electron spectroscopy and microscopy applied to chemical and structural analysis of hair.

The application of surface specific x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) will be shown to be an effective means for the elucidation of hair fiber surface chemistry and structure. Example studies of bleaching and fiber conditioning treatments are discussed. The bleached fiber surface is found to become more hydrophilic due to the loss of the naturally occurring hydrocarbon overlayer and oxidation of surface functional groups as a result of bleaching. Comparison between generic bleaching regimens illustrates the importance of increased pH and the presence of surfactant for effective treatment. Adsorption of conditioning diester quat and dimethicone molecules reintroduces a hydrophobic like surface layer on the hair fiber. Spectroscopic data indicated a segregated adsorption structure of the chemically different conditioning molecules. Electron microscope images of the conditioned hair shows a smooth uniform surface.