Hair resistance to mechanical wear

Abstract

Hair mechanical properties are primary indicators of hair integrity. Here we describe a methodology based on hair's resistance to mechanical wear to evaluate cosmetic treatments. Using a vibrational vortex cycle, we developed a protocol that relies on the plastic deformation and degradation of hair, due to frictional forces between hardened steel balls and hair fragments. We demonstrate that the balls when in contact with the hair fragments promoted extended hair degradation. The degree of degradation was related to hair's resistance to mechanical wear. Lower degradation rates reflect high resistance to mechanical wear. We found differences according to hair ethnicity and type of treatment. This methodology shows great potential for the screening and evaluation of the effect of cosmetic treatments on hair.