title: Phase Transition and Dynamics in Imidazolium-Based Ionic Liquid Crystals through a Metastable Highly Ordered Smectic Phase.
abstract: The phase transition behavior and dynamics of ionic liquid crystals, 1-methyl-3-alkylimidazolium tetrafluoroborate with various alkyl chain lengths, were investigated by X-ray scattering, differential scanning calorimetry, optical microscopy, and dielectric relaxation spectroscopy to elucidate the mechanism of their structural and phase changes. A metastable phase was found to appear via a supercooled smectic phase on cooling. In the metastable phase, disorder in the smectic phase is partially frozen; thus, the phase has order higher than that of the smectic phase but lower than that of the crystalline phase. During the subsequent heating process, the frozen disorder activates, and a crystalline phase appears in the supercooled smectic phase before entering the smectic phase. The relationship between the phase behavior and the dynamics of charge carriers such as ions is also discussed.
authors.affiliation: Department of Physics, Ritsumeikan University , Noji-Higashi 1-1-1, Kusatsu 525-8577, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Nozaki
authors.affiliation: Department of Physics, Ritsumeikan University , Noji-Higashi 1-1-1, Kusatsu 525-8577, Japan.
authors.forename: Keito
authors.initials: K
authors.lastname: Yamaguchi
authors.affiliation: Department of Physics, Ritsumeikan University , Noji-Higashi 1-1-1, Kusatsu 525-8577, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Tomida
authors.affiliation: Department of Physics, Ritsumeikan University , Noji-Higashi 1-1-1, Kusatsu 525-8577, Japan.
authors.forename: Natsumi
authors.initials: N
authors.lastname: Taniguchi
authors.affiliation: Department of Physics, Ritsumeikan University , Noji-Higashi 1-1-1, Kusatsu 525-8577, Japan.
authors.forename: Hironori
authors.initials: H
authors.lastname: Hara
authors.affiliation: Department of Physics, Ritsumeikan University , Noji-Higashi 1-1-1, Kusatsu 525-8577, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Takikawa
authors.affiliation: Department of Physics, Ritsumeikan University , Noji-Higashi 1-1-1, Kusatsu 525-8577, Japan.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Sadakane
authors.affiliation: Department of Physics, Ritsumeikan University , Noji-Higashi 1-1-1, Kusatsu 525-8577, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Nakamura
authors.affiliation: Graduate School of Human and Environmental Studies, Kyoto University , Kyoto 606-8501, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Konishi
authors.affiliation: Department of Physics, Ritsumeikan University , Noji-Higashi 1-1-1, Kusatsu 525-8577, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Fukao