title: Optically Isotropic Homochiral Structure Produced by Intercalation of Achiral Liquid Crystal Trimers.
abstract: Dark conglomerates of domains with opposite handedness, which are designated dark conglomerate phases (DC phases), have attracted much attention. We prepared an achiral liquid crystal trimer, 4,4'-bis{9-[4-(5-octyloxypyrimidin-2-yl)phenyloxy]nonyloxy}biphenyl (I-9), and investigated the physical properties. A droplet of trimer I-9 formed a conventional nematic phase on cooling from the isotropic liquid, and then changed to an optical isotropic phase with homochirality. X-ray diffraction measurements reveal that the isotropic phase has an intercalated layer structure with a correlation length of 95 nm. We prepared binary mixtures with a nematic liquid crystal, 4'-hexyloxy-4-cyanobiphenyl (6OCB). The mixtures containing 30-75 mol % of 6OCB exhibited smectic phases above the isotropic phase. We investigated mesogenic properties of trimer I-n (n = 5-9) depending on the parity of the linking group. Only trimer I-9 possessing the longest odd-numbered spacers showed the chiral isotropic phase, suggesting that a rigid bent structure is not necessary for the appearance of the isotropic phase. The experimental results reveal that trimer I-9 exhibits a soft crystalline DC phase representing a new modification of chiral symmetry breaking in lamellar liquid crystal phases.
authors.affiliation: Department of Frontier Materials Chemistry, Graduate School of Science and Technology, Hirosaki University , 3 Bunkyo-cho, Hirosaki, Aomori 036-8561, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Yoshizawa
authors.affiliation: Department of Frontier Materials Chemistry, Graduate School of Science and Technology, Hirosaki University , 3 Bunkyo-cho, Hirosaki, Aomori 036-8561, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Kato
authors.affiliation: Department of Frontier Materials Chemistry, Graduate School of Science and Technology, Hirosaki University , 3 Bunkyo-cho, Hirosaki, Aomori 036-8561, Japan.
authors.forename: Haruna
authors.initials: H
authors.lastname: Sasaki
authors.affiliation: Department of Physics, Graduate School of Science, Kyoto University , Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto, 606-8562, Japan.
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Takanishi
authors.affiliation: Department of Physics, Graduate School of Science, Kyoto University , Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto, 606-8562, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Yamamoto