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Liquid Crystal Alignment Properties of Poly‐(3‐thiopheneacetate)/Dialkyldimethylammonium Complexes
Author(s) -
Yoon YoungSik,
Kang Hyo,
Kim Byoung Gak,
Lee JongChan
Publication year - 2010
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.200900368
Subject(s) - homeotropic alignment , alkyl , liquid crystal , bromide , absorption (acoustics) , crystallography , chemistry , materials science , polymer chemistry , polymer , organic chemistry , optoelectronics , composite material
Liquid crystal alignment properties were investigated in liquid crystal (LC) cells fabricated with poly(3‐thiopheneacetate)/dialkyldimethylammonium (PTA‐C n ) complexes, where n is the number of carbon atoms in the alkyl groups in dialkyldimethylammonium bromide. Homeotropic LC alignment was observed in PTA‐C n LC cells containing long alkyl groups ( n = 14, 16, 18) with high pretilt angles close to 90°. Homeotropic LC alignment was observed from prepared LC cell made from PTA‐C12 film, while the homeotropic LC alignment was gradually changed to random alignment within 10 min. LC cells fabricated from PTA‐C10 always showed random alignment behavior. The surface orientational order parameters of the alkyl groups of PTA‐C n films were estimated by near edge X‐ray absorption fine structure (NEXAFS) spectroscopy, producing values of 0.040, 0.111, 0.153, 0.151, and 0.170 for PTA‐C10, PTA‐12, PTA‐14, PTA‐16, and PTA‐18, respectively. Therefore, homeotropic LC alignment behavior correlated well with the order of alkyl groups on the complex surface.