Dependence of In-plane anisotropy in polyimide Langmuir-Blodgett films on molecular weight of polyamic acid

The relation between molecular weight of polyamic acid and inplane anisotropy in the LB films was investigated. As the molecular weight increases, orientation order of the polymer chains to the dipping direction in the LB films and that of the liquid crystal on the LB films become uniform. The orien...

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Bibliographic Details
Published inJapanese Journal of Applied Physics Vol. 30; no. 1; pp. 131 - 135
Main Authors SORITA, T, MIYAKE, S, FUJIOKA, H, NAKAJIMA, H
Format Journal Article
LanguageEnglish
Published Tokyo Japanese journal of applied physics 1991
Subjects
Applied sciences
Crystallization
Exact sciences and technology
Organic polymers
Physicochemistry of polymers
Properties and characterization
Molecular orientation
Polymer
Experimental study
Liquid crystals
Molecular weight
Organic compounds
Thin film
Langmuir Blodgett method
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Summary:The relation between molecular weight of polyamic acid and inplane anisotropy in the LB films was investigated. As the molecular weight increases, orientation order of the polymer chains to the dipping direction in the LB films and that of the liquid crystal on the LB films become uniform. The orientation of liquid crystal is seemed to reflect that of the polymer chains. The experimental results can be qualitatively explained by the flow orientation model. It is assumed that origin for orientation of the polymer chains is attributed to the flow in vicinity of a substrate during dipping. The spreading solution stored for over a week results in inferior quality LB film as an alignment layer. Refering to the molecular weight dependence, it is thought that the degradation of the solution is caused by lowering of the molecular weight of polyamic acid due to hydrolysis.
ISSN:0021-4922
1347-4065
DOI:10.1143/jjap.30.131