Biomechanics of Chemically Treated Hair for Continuous 1D Strands

This study examines the biomechanical properties of chemically treated human hair strands, focusing on their tensile behavior and structural integrity. NaOH-treated hair strands showed the most favorable mechanical performance, with a Young's modulus of 207 MPa and ultimate tensile strength of 34 MPa, due to partial cuticle lifting that increased surface roughness without damaging the cortex. This treatment resulted in enhanced fiber cohesion and load distribution, making NaOH-treated strands suitable for textile applications. In contrast, formic acid (FA) treatment caused significant cuticle and cortex damage, leading to weaker mechanical properties, while bleach-treated strands exhibited intermediate characteristics. The findings suggest that moderate decuticularization with NaOH enhances spinnability and inter-fiber friction without compromising mechanical performance, indicating potential for developing hair-based biomaterials for textile-like and biomedical applications.