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Liquid crystal alignment property of n ‐alkylthiomethyl‐ or n ‐alkylsulfonylmethyl‐substituted polystyrenes
Author(s) -
Kang Hyo,
Park Jin Seol,
Kang Daeseung,
Lee JongChan
Publication year - 2009
Publication title -
polymers for advanced technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.61
H-Index - 90
eISSN - 1099-1581
pISSN - 1042-7147
DOI - 10.1002/pat.1314
Subject(s) - homeotropic alignment , materials science , alkyl , liquid crystal , polymer , side chain , surface energy , thioether , dielectric , polymer chemistry , crystallography , pendant group , chemical engineering , composite material , organic chemistry , optoelectronics , chemistry , engineering
We synthesized a series of n ‐alkylthiomethyl‐substituted polystyrenes (#T‐PS, # = 4, 8, 12, and 16) and n ‐alkylsulfonylmethyl‐substituted polystyrenes (#S‐PS, # = 4, 8, 12, and 16), where # is the number of carbon atoms in the n ‐alkyl side group of the polymers, using polymer analogous reactions to investigate their liquid crystal (LC) alignment properties. In general, the LC cell fabricated using the polymer film having a longer n ‐alkyl side group, a thioether linkage group, and a higher molar content of n ‐alkyl side group showed homeotropic LC alignment behavior with a pretilt angle of about 90°. The homeotropic alignment behavior was well correlated with the surface energy of the polymer films; when the positive dielectric anisotropic LC (ZLI‐5900‐000 from Merck) and negative dielectric anisotropic LC (MLC‐7026‐000 from Merck) were used to fabricate the LC cells, homeotropic alignment was observed when the surface energy values of the polymer were smaller than about 25 and 32 mJ/m 2 , respectively. Copyright © 2009 John Wiley & Sons, Ltd.