Electrospinning from room temperature ionic liquids for biopolymer fiber formation

Polymer electrospinning has emerged as a powerful technique for the fabrication of nanofibrous materials with high specific surface areas, controllable compositions, and high porosities for a wide range of applications. The electrospinning of biopolymers for fiber formation is of particular interest not only because the resources are renewable, but also because of the desirable characteristics of these biomacromolecules, including biocompatibility, biodegradability, and exquisite specificity. Electrospinning has routinely relied on organic solvents for the dissolution of polymeric materials, which are evaporated in the course of nanofiber formation. Most biopolymers, however, are insoluble in organic solvents so they cannot be electrospun using conventional approaches. Room temperature ionic liquids (RTILs) offer a solution to overcome these difficulties due to their exceptional solvent properties, allowing the electrospinning of recalcitrant biopolymers like cellulose. Moreover, non-volatile RTILs can provide a 'greener' processing alternative by preventing the release of harmful volatile compounds to the environment. This review provides an overview of the advantages and challenges of polymer electrospinning from highly conductive, non-volatile RTIL solutions, emphasizing the utility of RTILs in the dissolution of biopolymers, and the fabrication of advanced functional biopolymer composite fibers.