title: Orientational ordering of crystal domains in ionic liquid based mixtures.
abstract: By in situ observations using simultaneous X-ray diffraction and the DSC (differential scanning calorimetry) method, the effect of water, methanol, ethanol, and benzene on the crystallization has been observed in an ionic liquid (IL)-rich phase. The IL is a hydrophilic ionic liquid, N, N-diethyl-N-methyl-N-2-methoxyethyl ammonium tetrafluoroborate, [DEME][BF4]. At a small amount of the above additional molecules in the IL, the conventional preferred orientation on the Debye rings was seen by the X-ray diffraction. At 0.9 mol % H2O, twinlike crystal domains develop extraordinary on the microdomains. By the "crystal-growth enhancement effect" at a slight amount of water, a composite domain structure, which consists of the large domain and the weakly orientated microdomains, is formed without internal strains. Above 2.9 mol % H2O, the domain structure, however, disappears completely. It is remarkable that, in a thermal cycling experiment using pure [DEME][BF4], the similar composite domain structure appeared. This is also caused by an uptake of a slight amount of water.
authors.affiliation: Department of Materials Science and Engineering, National Defense Academy, Yokosuka 239-8686, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Imai
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Abe
authors.forename: Takefumi
authors.initials: T
authors.lastname: Goto
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Yoshimura
authors.forename: Shogo
authors.initials: S
authors.lastname: Kushiyama
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Matsumoto