Wetting behavior of human hair fibers

The wetting behavior of human hair in water has been investigated using a technique based on the Wilhelmy balance principle. The experimental technique makes it possible to study the relaxation effects occurring at the solid–liquid–air interface. The results strongly suggest that interactions between the solid and the liquid make important contributions to wettability of the solid surface because of reversible reorientation of polar groups at the interface. The effects of scale structure, weathering, and mechanical damage on wettability of the fiber surface are discussed. Surface roughness of the fiber plays an important role in wetting hysteresis.