Mechanically strong all-chitin filaments: Wet-spinning of β-chitin nanofibers in aqueous NaOH.

Herein, a facile wet-spinning strategy was used for the fabrication of mechanically strong all-chitin filaments from an aqueous NaOH solution using β-chitin nanofibers (β-ChNFs). It is hypothesized that to reach high mechanical performance it is important to preserve the crystalline structure of chitin during fabrication. To explore this possibility, β-ChNFs were disintegrated from squid pens by a mild procedure and showed a uniform diameter of 10-25 nm, length of a few microns, and a high aspect ratio of more than 200.