Fabrication of nanostructured and microstructured chitin materials through gelation with suitable dispersion media

Abstract

Recent developments in the fabrication of nano-and microstructured chitin materials are reviewed, specifically focusing on approaches through gelation with suitable dispersion media. Although chitin is one of the most abundant natural polysaccharides, it is under-used as a result of its poor solubility and difficulties in processing.The dissolution of chitin in different solvent systems, including ionic liquids, has been investigated for the production of various materials. For example, the ionic liquid 1-allyl-3-methylimidazolium bromide dissolved chitin at concentrations up to 5% w/w and formed ion gels at higher concentrations of chitin. A highly concentrated solution of CaBr 2 $2H 2 O/methanol also induced the gelation of chitin. As one of the most efficient methods of production of nanomaterials from chitin, self-assembled nanofibers have been fabricated by regeneration from solutions or gels of chitin with the appropriate solvents and dispersion media using a bottom-up approach. For example, a chitin ion gel with 1-allyl-3-methylimidazolium bromide was regenerated using methanol to produce a chitin nanofiber dispersion, which was then used to construct a film with a highly entangled nanofiber morphology by filtration. Physical and chemical approaches have been investigated for the fabrication of composite materials of self-assembled chitin nanofibers with other polymeric components.Poly(vinyl alcohol) and carboxymethyl cellulose were made compatible with chitin nanofibers by coregeneration and electrostatic interaction procedures, respectively. Surface-initiated graft polymerization of some monomers from chitin nanofiber films with the appropriate initiating groups have been conducted using the latter approach to obtain composite films covalently linked to graft chains on the nanofibers. Regeneration from gels with CaBr 2 $2H 2 O/methanol resulted in the efficient production of microporous materials.

Preparation and Grafting Functionalization of Self-Assembled Chitin Nanofiber Film

“…Surface-initiated graft polymerization of cyclic and vinyl monomers from the self-assembled chitin nanofiber film has been conducted to fabricate composite materials [33]. Such composites can be expected to exhibit specific functions such as influence of interfacial adhesion on mechanical properties [36][37][38].…”

“…From the ion gel, chitin self-assembled into nanofibers by regeneration, which further formed a nanofiber film by entanglement [30][31][32]. Moreover, surface-initiated graft polymerization from the nanofiber film has been conducted to produce chitin nanofiber-graft-synthetic polymer composite materials [33]. In this review article, the comprehensive results on the preparation and grafting functionalization of the self-assembled chitin nanofiber film are presented.…”

Preparation of Functional Xanthan Gum Materials Using Ionic Liquid

“…Over the past decade, ionic liquids, which are low-melting point salts and show liquid state at temperatures below the boiling point of water, have been identified as good solvents for polysaccharides such as cellulose [6][7][8][9][10][11][12][13][14] since an ionic liquid, 1-butyl-3-methylimidazolium chloride (BMIMCl, figure 1), was found to dissolve cellulose in relatively high concentrations [15]. The formation of ion gels of polysaccharides, e.g., cellulose, chitin, and so on, with ionic liquids has also been reported; and through such gelation, material processing is further conducted to obtain polysaccharide-based hydrogel, cryogel, film, and nanofiber [16][17][18][19][20]. On the basis of these studies, ionic liquids have been well accepted as the useful media to provide new polysaccharide-based functional materials.…”

Fabrication of cationic chitin nanofiber/alginate composite materials

“…Therefore, the researches concerning the incorporation of chitin into functional bio-based materials have attracted much attention even in recent years. One of the efficient approaches to fabricate chitin-based functional materials is nanofibrillation, such as nanofibers and nanowhiskers [10][11][12][13][14][15][16]. Break down the starting bulk fibril materials from native chitin by appropriate treatments in water has mainly been conducted to induce nanofibrillation, such as grinding mechanical technique and electrostatic repulsion by the introduction of carboxylate groups [17][18][19][20][21].…”