Structure Evolution in Hair Fibers During Strain and the Effect of Relative Humidity

This study investigates the structural evolution of hair fibers under strain and the effect of relative humidity on this process. Using Raman spectroscopy and wide-angle X-ray scattering (WAXS), the researchers observed that keratin in hair undergoes two main transitions from α-helix to β-sheet structures, which are influenced by humidity levels. These transitions occur through a disordered state, and water plays a crucial role in modifying the hair matrix, affecting the strain at which intermediate filaments unfold. The findings provide new insights into the mechanical behavior of hair and the conditions that influence its structural changes.