Triboelectric properties on treated human hair: a mesoscale method to measure the surface potential

Abstract

The anti-static effect is an increasingly valuable asset for hair treatment products, holding an increasing economic share. Hair care industries are increasingly looking for quantitative methods for hair treatment assessment, yet the multiscale nature of hair challenges the comparative assessment of its triboelectric properties. This study presents a straightforward methodology for measuring the surface potential of human hair at the mesoscale. Instead of studying microscale local charges highly accurately or bundling large bunches of hair for averaging, an intermediate approach was designed. The method was validated by varying both the hair count and the sample distance from the sensor. The results showed that the method can distinguish the surface charge of bleached hair from those of chemically untreated or mildly peptide treated. The variations in static charge were linked to the hair properties after the treatments, as assessed by Fourier transform infrared spectroscopy and scanning electron microscopy. The availability of a relatively simple technique to obtain quantified measurements of hair condition after treatment will enable hair care product manufacturers to identify potential defects, ensuring their products treat damaged hair to the required specifications and quality standards.