Strong fibrous filaments nanocellulose crystals prepared by self-twisting microfluidic spinning

Orderly arranged nanocellulose and its composite materials have low density and excellent mechanical properties. A self-twisted microfluidic chip is designed in this work. Its sheath channel and core channel form a staggered layer structure. This structure can make the Cellulose nanocrystals (CNCs) in the core flow undergo twist during the gel forming process, so that it can be better combined and its mechanical properties can be improved. The degree of orientation and mechanical properties of fiber filaments were studied by wide-angle X-ray scattering and universal tensile testing machine. The orientation degree of the fiber is 0.77, the tensile strength is 400 ± 20 MPa, and the Young ' s modulus is 37.3 ± 3.8 GPa. The torsion angle of fiber surface is 5.5°. The mechanical properties of the filaments are 150% higher than those of a previously reported filament made of pure CNCs. This work demonstrates the possibility of preparing high-strength CNCs fiber filaments. [Display omitted] •The microfluidic chip with staggered layer structure can make CNCs self-twist when forming gel fibers.•The CNCs fiber orientation is 0.77.•The tensile strength and Young ' s modulus of CNCs fiber can reach 400 MPa and 37.3Gpa, respectively.