A Two-Phase Structure for Keratin Fibers

A two-phase structure is proposed for keratin fibers consisting of a water-absorbing matrix M, in which non-water-absorbing cylinders of phase C are embedded. The cylinders of phase C are parallel to the fiber direction. The main assumption made is that only the mechanical moduli of phase M are affected by moisture uptake as long as the fiber is not stretched. On this basis, using the longitudinal and radial swelling data available, quantitative relationships between the dry and wet Young's Moduli and rigidity moduli were obtained which agreed with experimental results. Further, other physical observations were shown to be compatible with this model.