Light-driven electrohydrodynamic instabilities in liquid crystals

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55 Downloads (Pure)

Abstract

The induction of electrohydrodynamic instabilities in nematic liquid crystals through light illumination are reported. For this purpose, a photochromic spiropyran is added to the liquid crystal mixture. When an electrical field is applied in the absence of UV light, the homeotropic liquid crystal reorients perpendicular to the electrical field driven by its negative dielectric anisotropy. Upon exposure to UV light, the nonionic spiropyran isomerizes to the zwitterionic merocyanine form inducing electrohydrodynamic instabilities which turns the cell from transparent into highly scattering. The reverse isomerization to closed-ring spiropyran form occurs thermally or under visible light, which stops the electrohydrodynamic instabilities and the cell becomes transparent again. It is demonstrated that the photoionic electrohydrodynamic instabilities can be used for light regulation. Local exposure, either to drive the electrohydrodynamics or to remove them enables the formation of colored images.

Original languageEnglish
Article number1707436
Number of pages7
JournalAdvanced Functional Materials
Volume28
Issue number21
DOIs
Publication statusPublished - 2018

Fingerprint

Liquid Crystals
Electrohydrodynamics
electrohydrodynamics
Liquid crystals
liquid crystals
Ultraviolet radiation
Nematic liquid crystals
Isomerization
cells
isomerization
induction
Anisotropy
Lighting
illumination
Scattering
anisotropy
rings
scattering
spiropyran

Keywords

  • Electrohydrodynamic instabilities
  • Light scattering
  • Liquid crystals
  • Photochemistry

Cite this

@article{41d6a91cb63344589402f23afa48c2ea,
title = "Light-driven electrohydrodynamic instabilities in liquid crystals",
abstract = "The induction of electrohydrodynamic instabilities in nematic liquid crystals through light illumination are reported. For this purpose, a photochromic spiropyran is added to the liquid crystal mixture. When an electrical field is applied in the absence of UV light, the homeotropic liquid crystal reorients perpendicular to the electrical field driven by its negative dielectric anisotropy. Upon exposure to UV light, the nonionic spiropyran isomerizes to the zwitterionic merocyanine form inducing electrohydrodynamic instabilities which turns the cell from transparent into highly scattering. The reverse isomerization to closed-ring spiropyran form occurs thermally or under visible light, which stops the electrohydrodynamic instabilities and the cell becomes transparent again. It is demonstrated that the photoionic electrohydrodynamic instabilities can be used for light regulation. Local exposure, either to drive the electrohydrodynamics or to remove them enables the formation of colored images.",
keywords = "Electrohydrodynamic instabilities, Light scattering, Liquid crystals, Photochemistry",
author = "Yuanyuan Zhan and Schenning, {Albertus P.H.J.} and Broer, {Dirk J.} and Guofu Zhou and Danqing Liu",
year = "2018",
doi = "10.1002/adfm.201707436",
language = "English",
volume = "28",
journal = "Advanced Functional Materials",
issn = "1616-301X",
publisher = "Wiley-VCH Verlag",
number = "21",

}

Light-driven electrohydrodynamic instabilities in liquid crystals. / Zhan, Yuanyuan; Schenning, Albertus P.H.J.; Broer, Dirk J.; Zhou, Guofu; Liu, Danqing.

In: Advanced Functional Materials, Vol. 28, No. 21, 1707436, 2018.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Light-driven electrohydrodynamic instabilities in liquid crystals

AU - Zhan, Yuanyuan

AU - Schenning, Albertus P.H.J.

AU - Broer, Dirk J.

AU - Zhou, Guofu

AU - Liu, Danqing

PY - 2018

Y1 - 2018

N2 - The induction of electrohydrodynamic instabilities in nematic liquid crystals through light illumination are reported. For this purpose, a photochromic spiropyran is added to the liquid crystal mixture. When an electrical field is applied in the absence of UV light, the homeotropic liquid crystal reorients perpendicular to the electrical field driven by its negative dielectric anisotropy. Upon exposure to UV light, the nonionic spiropyran isomerizes to the zwitterionic merocyanine form inducing electrohydrodynamic instabilities which turns the cell from transparent into highly scattering. The reverse isomerization to closed-ring spiropyran form occurs thermally or under visible light, which stops the electrohydrodynamic instabilities and the cell becomes transparent again. It is demonstrated that the photoionic electrohydrodynamic instabilities can be used for light regulation. Local exposure, either to drive the electrohydrodynamics or to remove them enables the formation of colored images.

AB - The induction of electrohydrodynamic instabilities in nematic liquid crystals through light illumination are reported. For this purpose, a photochromic spiropyran is added to the liquid crystal mixture. When an electrical field is applied in the absence of UV light, the homeotropic liquid crystal reorients perpendicular to the electrical field driven by its negative dielectric anisotropy. Upon exposure to UV light, the nonionic spiropyran isomerizes to the zwitterionic merocyanine form inducing electrohydrodynamic instabilities which turns the cell from transparent into highly scattering. The reverse isomerization to closed-ring spiropyran form occurs thermally or under visible light, which stops the electrohydrodynamic instabilities and the cell becomes transparent again. It is demonstrated that the photoionic electrohydrodynamic instabilities can be used for light regulation. Local exposure, either to drive the electrohydrodynamics or to remove them enables the formation of colored images.

KW - Electrohydrodynamic instabilities

KW - Light scattering

KW - Liquid crystals

KW - Photochemistry

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U2 - 10.1002/adfm.201707436

DO - 10.1002/adfm.201707436

M3 - Article

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VL - 28

JO - Advanced Functional Materials

JF - Advanced Functional Materials

SN - 1616-301X

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