Ultra-Strong Regenerated Wool Keratin Fibers Regulating via Keratin Conformational Transition

Abstract

By virtue of remarkable biocompatibility and their promising applications in biomedical fields, biomass-regenerated fibers, such as wool keratin fiber and cellulose fiber, have attracted extensive attention. However, the insufficient mechanical performance still hinders their yarn manufacturing capability and further large-scale applications. Herein, an ultra-strong and ultra-tough regenerated wool keratin fiber by regulating keratin conformation with high-quality small-size graphene (HQSGr) and mechanical training treatment (M-HQSGr-RWKF) is fabricated. With the assistance of mechanical training, a small addition of HQSGr (0.1 wt.%) remarkably augments the secondary structure transition from α-helix to β-sheet of the keratin, which delivers a tensile strength of 215.4 ± 5.2 MPa, surpassing all reported natural wool and regenerated wool or even poultry fibers. Benefiting from the excellent mechanical strength, wet-state toughness (158.9 MJ m−3), and recoverable strain (205.0%), M-HQSGr-RWKF has been demonstrated as a biocompatible artificial muscle to drive the biomimetic motion, which manifests ultrahigh actuation strain greater than 100.0% and stress of 16.7 MPa. The derived ultra-strong and ultra-tough keratin fiber opens a new avenue for developing smart fiber from biomass resources.