A novel strategy to reduce the viscosity of cellulose-ionic liquid solution assisted by transition metal ions

The high viscosity of ionic liquids, even at relatively high temperatures, can greatly affect the production of cellulose fibers through the wet-spinning process. The high viscosity mainly by due to the hydrogen bond interaction between the cations and anions of ionic liquids. It is possible to reduce the viscosity by modulating the hydrogen bond interaction. In the present work, copper chloride (CuCl₂) was dissolved in 1-butyl-3-methylimidazolium chloride ([Bmim]Cl)-cellulose solution, followed by the formation of a complex with the chloride anions by converting it to [CuCl₄]^2- anion. Through this strategy, the extrusion velocity of the solution improved, and the produced fibers obtained smoother surfaces and shrunken diameters.