Processing and Microfabrication of Self-Assembled Chitin Nanofibers and Composites
Chitin (poly-(1,4)-N-acetyl-D-glucosamine) is the second most abundant natural polysaccharide after cellulose and is synthesized by a number of living organisms. Due to strong intermolecular hydrogen bonds, chitin is insoluble in water, diluted acid/base solutions and most organic solvents. The intractability and water insolubility of chitin impedes the use of water-based self-assembly generative route, which is common in the synthesis of other biogenic nanofibrils. We found that chitin dissolves in the solvent Hexafluoroisopropanol (HFIP) and self-assemble into 3nm nanofibers upon drying from solution, named chitin nanofiber ink. Chitin nanofiber ink provides great advantages to manufacture macro- and micro scale structures without disrupting the delicate nanoscale molecular self-assembly process. In this work first I use the nanofiber ink to fabricate macro scale nanofiber chitin films and study the structure-properties-processing relationships. Then I use the nanofiber ink to microfabricate nanofiber chitin substrates on supported platforms and free-standing films with micro-structures desired for tissue engineering. Finally I explored chitin silk composites nanofiber self-assembly.