Thermoreversible helical fibers from photoreactive triphenylene-derived liquid crystals in liquid paraffin

Takuji Hirose; Yuka Kikuchi; Tomoaki Nakano; Tsukasa Ohno; Kengo Kawamura; Normazliana Binti Nazri; Atsuhiro Fujimori; Koichi Kodama; Mikio Yasutake

doi:10.1016/j.heliyon.2023.e22037

Thermoreversible helical fibers from photoreactive triphenylene-derived liquid crystals in liquid paraffin

Heliyon. 2023 Nov 10;9(11):e22037. doi: 10.1016/j.heliyon.2023.e22037. eCollection 2023 Nov.

Authors

Takuji Hirose¹, Yuka Kikuchi¹, Tomoaki Nakano¹, Tsukasa Ohno¹, Kengo Kawamura¹, Normazliana Binti Nazri², Atsuhiro Fujimori¹, Koichi Kodama¹, Mikio Yasutake¹

Affiliations

¹ Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakura, Saitama, 338-8570, Japan.
² Department of Applied Chemistry, Saitama University, 255 Shimo-ohkubo, Sakura, Saitama, 338-8570, Japan.

Abstract

Liquid crystalline triphenylene derivatives, TPC1_p-n (n = 6, 12, 14, 16) were prepared using p-alkoxycinnamate as the [2+2] photo-cyclization site. TPC1_p-n (n = 12, 14, 16) showed Col_r phase and gave crescent-shaped or helical fibers after UV-irradiated in liquid paraffin solutions at 90 and 110 °C in the Col_r temperature range. The apparent photoreaction products were shown to be thermally reversible, i.e. they dissolved in liquid paraffin at high temperatures and reappeared on cooling, indicating that they were aggregates of oligomerized TPC1_p-n. The reaction mechanism was discussed in terms of the structure of the liquid crystalline phase.

Keywords: Assembly; Helical fiber; Photocyclization reaction; Thermal reversibility; Triphenylene-derived liquid crystal.