Photoinduced gliding of the surface director in azo‐dye doped nematic liquid crystals

Abstract

We report photoinduced surface director gliding with azo dye-doped nematic liquid crystals. This gliding has the same characteristics as that induced by an applied magnetic field. Fast and slow dynamic regimes are observed, the latter fitting to a stretched exponential. In addition, the gliding demonstrates a 'sensitizing' effect for sequential measurements.

Effect of Azo Dyes Molecules Dimerization on Properties of LC – Dye Systems Under Laser Irradiation

“…К наиболее перспективным методам полу-чения ориентированных ЖК относится их ориен-тирование в системах ЖК-краситель с помощью светового или лазерного излучения [2][3][4][5][6][7][8][9][10][11][12][13]. Этот эффект называется фотоориентацией.…”

Electrically assisted light-induced azimuthal gliding of the nematic liquid-crystal easy axis on photoaligned substrates

“…Over the past few decades this slow motion -the socalled easy axis gliding -has received much attention * Email address: kiselev@iop.kiev.ua † Email address: eechigr@ust.hk as a widespread phenomenon observed in a variety of liquid crystals on amorphous glass [3], polymer [4][5][6][7][8][9][10][11][12][13] and solid [6,11] substrates. Recently, it was found that, in addition to magnetically (electrically) induced gliding, there is the photoinduced gliding of the easy axis in dye-doped liquid crystals [14,15]. According to Ref.…”

Anchoring strength of o-, m-, and p -methyl red-dye-doped nematics on rubbed and unrubbed polyimide surfaces

“…Evidence exists of photoinduced reorientation of the easy axis at the liquid crystal/polymer surface associated with photo-excitation and trans to cis isomerization of the dye 4,5 . In particular, it has been observed that liquid crystal samples doped with the azo dye methyl red and one surface coated with fluorinated polyvinyl cinnamate (PVCN-F) demonstrate a significant amount of reorientation of the easy axis on that surface 6,7,8 .…”

“…Our work has involved comparing the effects of various azo dyes, their interactions with polymer substrates, both rubbed and unrubbed, and the anchoring strength between these dyes and the liquid crystals. Recently, we measured photoinduced azimuthal reorientation on rubbed PI using DO3 doped nematics 5 . We have also found that this photoinduced reorientation of the easy axis involves a memory effect, consistent with the results of Ouchi, et al 13 .…”