Semidilute solution structure of cellulose in an ionic liquid and its mixture with a polar organic co‐solvent studied by small‐angle X‐ray scattering

ABSTRACT Structural and thermodynamic properties of cellulose solutions in the ionic liquid 1‐ethyl‐3‐methylimidazolium acetate (EMIMAc) and its binary mixtures with N,N‐dimethyl formamide (DMF) are studied by small‐angle X‐ray scattering (SAXS). These measurements indicate molecular dissolution of the cellulose chains without any significant aggregation. The power–law relationships of the evaluated correlation length and osmotic modulus to concentration exhibit exponents of −0.76 and 2.06 for EMIMAc and −0.80 and 2.14 for DMF/EMIMAc solvent mixture, respectively. Thus, these solvents can be considered to be good solvents for cellulose. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017, 55, 888–894 Cellulose is the most abundant biopolymer on earth, and new methods to dissolve it have garnered much interest. Solutions of cellulose in ionic‐liquid and its mixture with a polar organic co‐solvent are studied by small‐angle X‐ray scattering (SAXS) to evaluate the structure and thermodynamic solution properties. Till now, these were only evaluated by rheological measurements. The results provide direct evidence of molecular dissolution of the cellulose chains and show good solvent conditions.