Liquid Crystal Alignment Properties of Poly-(3-thiopheneacetate)/Dialkyldimethylammonium Complexes

✍ Scribed by Young-Sik Yoon; Hyo Kang; Byoung Gak Kim; Jong-Chan Lee

• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: English
• Weight: 457 KB
• Volume: 211
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.200900368

✦ Synopsis

Abstract

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.

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