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Photopolymerization and Molecular Orientational Order of the Discotic Nematic Phase in 2,3,6,7,10,11‐Hexakis(4‐(8‐acryloyloxyoctyloxy)benzoyloxy)triphenylene
Author(s) -
Ukon Masakatsu,
Sugino Takushi,
Watanabe Tsuyoshi,
Monobe Hirosato,
Shimizu Yo
Publication year - 2002
Publication title -
macromolecular materials and engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 96
eISSN - 1439-2054
pISSN - 1438-7492
DOI - 10.1002/1439-2054(200210)287:10<698::aid-mame698>3.0.co;2-k
Subject(s) - triphenylene , photopolymer , materials science , discotic liquid crystal , polymerization , homeotropic alignment , liquid crystal , phase (matter) , columnar phase , miscibility , mesophase , polymer , organic chemistry , chemistry , composite material , optoelectronics
A triphenylene‐based discotic liquid crystal, 2,3,6,7,10,11‐hexakis(4‐(8‐acryloyloxyoctyloxy)benzoyloxy)triphenylene (6ABTP) was investigated on the behavior of local order parameters for the discotic nematic (N D ) phase from the viewpoint of change of the molecular orientational order by photopolymerization. The local order parameters of the aromatic CC, CH and two CO bonds of the acryloyl and benzoyl CO groups were evaluated by an infrared dichroic method of Vij et al. It was found that 6ABTP tends to show a homeotropic alignment in the N D phase on a polyimide film spin‐coated on BaF 2 and the triphenylene core shows a large order parameter (ca. 0.4–1.0), while the CO moieties have a quite lower one (< 0.3). In order to investigate the disordering of molecular alignment due to crosslinking by photopolymerization, the behavior of local order parameters in photopolymerization was also evaluated. It was found that the order parameter of the aromatic core in the N D phase remarkably decreases at the early stage of photopolymerization, but only about 20% of decrease in the order parameter could be attained at the end of polymerization.Microscopic view of the texture for the film after photopolymerization at 120 °C.