Effect of methylene spacers in poly(methacrylate)s bearing styrylpyridine side chains on the ability to control liquid crystal alignment

Shigeru Yamaki, Masaru Nakagawa, Shin'ya Morino, Kunihiro Ichimura

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

The photochemistry, photoinsolubilization and ability to control surface-assisted liquid crystal (LC) alignment of poly(methacrylates) tethering styrylpyridine (SP) side chains through methylene spacers (m = 2, 6 and 12) are described. The extent of (2+2) photodimerization and E-to-Z isomerization of SP side chains was markedly affected by the length of methylene spacers. In the early stage of photoirradiation, the photodimerization took place preferentially for SP-polymers with a shorter methylene spacer, whereas the photodimerization was accompanied by the E-to-Z photoisomerization for the polymers with longer spacers even in the early stage of photoirradiation. Irradiation of thin films with linearly polarized light resulted in the generation of dichroism of SP moieties owing to the angular-selective consumption of E-isomer, leading to surface-assisted homogeneous LC aligment. The direction of LC photoalignment was reversed from perpendicular to parallel orientation when SP moieties were tethered to polymer backbones through spacers. The working mechanism of the alignment reversion was discussed, based on the angular-selective E-to-Z photoisomerization and photodimerization.

Original languageEnglish
Pages (from-to)354-361
Number of pages8
JournalMacromolecular Chemistry and Physics
Volume202
Issue number2
DOIs
Publication statusPublished - 2001 Feb 8
Externally publishedYes

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Polymers and Plastics
  • Materials Chemistry

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