Orientation of liquid crystalline blue phases on unidirectionally orienting surfaces

Misaki Takahashi, Takuma Ohkawa, Hiroyuki Yoshida, Junichi Fukuda, Hirotsugu Kikuchi, Masanori Ozaki

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Liquid crystalline cholesteric blue phases (BPs) continue to attract interest due to their fast response times and quasi-polarization-independent phase modulation capabilities. Various approaches have recently been proposed to control the crystal orientation of BPs on substrates; however, their basic orientation properties on standard, unidirectionally orienting alignment layers have not been investigated in detail. Through analysis of the azimuthal orientation of Kossel diagrams, we study the 3D crystal orientation of a BP material - with a phase sequence of cholesteric, BP I, and BP II - on unidirectionally orienting surfaces prepared using two methods: rubbing and photoalignment. BP II grown from the isotropic phase is sensitive to surface conditions, with different crystal planes orienting on the two substrates. On the other hand, strong thermal hysteresis is observed in BPs grown through a different liquid crystal phase, implying that the preceding structure determines the orientation. More specifically, the BP II-I transition is accompanied by a rotation of the crystal such that the crystal direction defined by certain low-value Miller indices transform into different directions, and within the allowed rotations, different azimuthal configurations are obtained in the same cell depending on the thermal process. Our findings demonstrate that, for the alignment control of BPs, the thermal process is as important as the properties of the alignment layer.

Original languageEnglish
Article number104003
JournalJournal of Physics D: Applied Physics
Volume51
Issue number10
DOIs
Publication statusPublished - Feb 19 2018

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Crystal orientation
Crystalline materials
Crystals
Liquids
liquids
crystals
alignment
Liquid Crystals
Phase modulation
Substrates
Liquid crystals
Hysteresis
Polarization
phase modulation
hysteresis
liquid crystals
diagrams
Hot Temperature
polarization
configurations

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Acoustics and Ultrasonics
  • Surfaces, Coatings and Films

Cite this

Orientation of liquid crystalline blue phases on unidirectionally orienting surfaces. / Takahashi, Misaki; Ohkawa, Takuma; Yoshida, Hiroyuki; Fukuda, Junichi; Kikuchi, Hirotsugu; Ozaki, Masanori.

In: Journal of Physics D: Applied Physics, Vol. 51, No. 10, 104003, 19.02.2018.

Research output: Contribution to journalArticle

Takahashi, Misaki ; Ohkawa, Takuma ; Yoshida, Hiroyuki ; Fukuda, Junichi ; Kikuchi, Hirotsugu ; Ozaki, Masanori. / Orientation of liquid crystalline blue phases on unidirectionally orienting surfaces. In: Journal of Physics D: Applied Physics. 2018 ; Vol. 51, No. 10.
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