title: True molecular solutions of natural cellulose in the binary ionic liquid-containing solvent mixtures.
abstract: Evidence is presented for the first time of true molecular dissolution of cellulose in binary mixtures of common polar organic solvents with ionic liquid. Cryogenic transmission electron microscopy, small-angle neutron-, X-ray- and static light scattering were used to investigate the structure of cellulose solutions in mixture of dimethyl formamide and 1-ethyl-3-methylimidazolium acetate. Structural information on the dissolved chains (average molecular weight ∼ 5 × 10(4)g/mol; gyration radius ∼ 36 nm, persistence length ∼ 4.5 nm), indicate the absence of significant aggregation of the dissolved chains and the calculated value of the second virial coefficient ∼ 2.45 × 10(-2)mol ml/g(2) indicates that this solvent system is a good solvent for cellulose. More facile dissolution of cellulose could be achieved in solvent mixtures that exhibit the highest electrical conductivity. Highly concentrated cellulose solution in pure ionic liquid (27 wt.%) prepared according to novel method, utilizing the rapid evaporation of a volatile co-solvent in binary solvent mixtures at superheated conditions, shows insignificant cellulose molecular aggregation.
authors.affiliation: Faculty of Chemical Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel. Electronic address: cerycdr@tx.technion.ac.il.
authors.forename: Dmitry M
authors.initials: DM
authors.lastname: Rein
authors.affiliation: Faculty of Chemical Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel. Electronic address: rafail@tx.technion.ac.il.
authors.forename: Rafail
authors.initials: R
authors.lastname: Khalfin
authors.affiliation: Jülich Centre for Neutron Science, Forschungszentrum Jülich GmbH Outstation at MLZ, 85747 Garching, Germany. Electronic address: n.szekely@fz-juelich.de.
authors.forename: Noemi
authors.initials: N
authors.lastname: Szekely
authors.affiliation: Faculty of Chemical Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel. Electronic address: yachinc@tx.technion.ac.il.
authors.forename: Yachin
authors.initials: Y
authors.lastname: Cohen
mesh_terms: D002482:Cellulose / Q000737:chemistry*; D002725:Chloroform / Q000737:chemistry; D020285:Cryoelectron Microscopy / Q000379:methods; D004126:Dimethylformamide / Q000737:chemistry; D007093:Imidazoles / Q000737:chemistry; D052578:Ionic Liquids / Q000737:chemistry*; D008970:Molecular Weight; D053838:Scattering, Small Angle; D012996:Solutions; D012997:Solvents / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D007093:Imidazoles; D052578:Ionic Liquids; D012996:Solutions; D012997:Solvents; D002725:Chloroform; D004126:Dimethylformamide; D002482:Cellulose; C518739:1-ethyl-3-methylimidazolium
keywords: Amorphous amphiphilic cellulose; Binary solvent mixture; Cellulose true molecular solution; Small-angle neutron and X-ray diffraction