Studies on the post-treatment of the dry-spun fibers from regenerated silk fibroin solution: Post-treatment agent and method

By mimicking the spinning process of silkworm, regenerated silk fibroin (RSF) biofibers were dry-spun from RSF aqueous solutions and then post-treated. The effects of post-treatment agents on the conformation, surface morphology, orientation and mechanical properties of the fibers were studied. Compared to inorganic salt system, alcohol/water system obviously induced the fibroin conformation transition from random coil/α-helix to β-sheet. In addition, the post-drawing process induced the orientation of the β-sheet crystallites, which contributed to the improved breaking stress of the fiber. When the fiber was drawn two times in 80 vol.% ethanol aqueous solution, and then immersed in the solution for 1 h, the breaking stress and the elongation at break of the fiber were increased to 199 MPa and 55%, respectively.