Surface potential measurement of human hair using Kelvin probe microscopy

Surface charge of human hair has a significant effect on manageability, feel, and appearance. For this reason, controlling charge buildup to improve these factors is an important issue in the commercial hair care industry. In this study the surface potential of human hair is measured using the Kelvin probe method with an atomic force microscope. Samples are mounted in conductive silver paint, and a dc voltage is applied through the sample puck. The potential on the sample surface is then measured with a conductive tip. Caucasian virgin (undamaged), chemically damaged, and mechanically damaged hair samples are studied to determine the effect of damaging treatments on surface charge properties, and the different effects of chemical and mechanical damages on surface potential. Samples treated with commercial conditioner as well as those treated with an amino silicone conditioner are also studied to determine the effect of conditioner treatment. Similarly, the effect of surrounding environment is studied by varying the relative humidity experienced by the sample. Mechanisms for the given results are discussed and recommendations given. (c) 2007 American Vacuum Society.