High molecular weight chitin fibers were electrospun in a one-pot process directly from a 1-ethyl-3-methylimidazolium acetate solution of chitin extracted from dried shrimp shell. Such a technology obviates the need not only for the many chemicals and the energy used in industrial isolation of chitin from crustacean shells but also saves the chemicals, energy, and time needed to prepare chitin spinning dopes.

To address the need to scale up technologies for electrospinning of biopolymers from ionic liquids to practical volumes, a setup for the multi-needle electrospinning of chitin using the ionic liquid 1-ethyl-3-methylimidazolium acetate, [C mim]-[OAc], was designed, built, and demonstrated. Materials with controllable and high surface area were prepared at the nanoscale using ionic-liquid solutions of high-molecular-weight chitin extracted with the same ionic liquid directly from shrimp shells.

We report the correlation between key solution properties and spinability of chitin from the ionic liquid (IL) 1ethyl-3-methylimidazolium acetate ([C 2 mim][OAc]) and the similarities and differences to electrospinning solutions of nonionic polymers in volatile organic compounds (VOCs). We found that when electrospinning is conducted from ILs, conductivity and surface tension are not the key parameters regulating spinability, while solution viscosity and polymer concentration are. Contrarily, for electrospinning of polymers from VOCs, solution conductivity and viscosity have been reported to be among some of the most important factors controlling fiber formation. For chitin electrospun from [C 2 mim][OAc], we found both a critical chitin concentration required for continuous fiber formation (>0.20 wt %) and a required viscosity for the spinning solution (between ca. 450−1500 cP). The high viscosities of the biopolymer−IL solutions made it possible to electrospin solutions with low, less than 1 wt %, polymer concentration and produce thin fibers without the need to adjust the electrospinning parameters. These results suggest new prospects for the control of fiber architecture in nonwoven mats, which is crucial for materials performance.

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