Transformation from Suspension to Anisotropic Microfiber in the System of the Cholesteric Liquid Crystalline Phase of Chitin-Nanowhisker with the Surface Modified by Chitosan

The strength of natural fibers is attributed to the anisotropic alignment of nano/microfibrils. To mimic this, the present work proposes a concentration-induced cholesteric liquid crystalline (CLC) phase for a suspension of chitin nanowhiskers surface-modified with chitosan (CTWK-CS). This phase enables the wet-spinning process to produce anisotropic microfibers. Although shear forces during spinning are expected to disturb the CLC structure, birefringent colors and TEM cross sections confirm its partial retention in the microfibers. Fiber tenacity is tunable through poststretching. Fiber dissolution in acetic acid indicates that inter- and intramolecular hydrogen bonding contribute critically to the structural integrity. This work demonstrates that the preorganization of nanowhiskers into a CLC phase allows the direct formation of ordered microfibers from colloidal suspension.