Document Detail


Distinguishing the parallel and vertical orientations and optic axis characteristics determination of azobenzene mesogen by conoscopic polarized microscopy.
MedLine Citation:
PMID:  21910731     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Orientational behaviours under the action of linearly polarized light and circularly polarized light of a side-chain azobenzene containing polymer were studied by conoscopic polarized microscopy. The results suggest that the linearly polarized light (473 nm, 20 mW cm(-2) ) results in an in-plane orientation of the azobenzene groups. The irradiation with circularly polarized light (473 nm, 20 mW cm(-2) ) leads to a tilt orientation (out-of-plane) of the azobenzene groups with the long axis of mesogens aligned along the propagation direction of the actinic light. Characteristic features of the in-plane and out-of-plane orientated films were obtained from their interference figures. The in-plane orientated film shows an interference cross consisting of a broad fuzzy bar, and the cross-centre lies in the centre of view field. In-plane orientated film also yields a flash figure upon a less than 10° rotation of the sample under polarized microscopy. The interference figures yielded from the out-of-plane orientated films consist of narrow bar cross. The locations of those interference figures depend on the oblique angle of the irradiation light. A method for distinguishing the in-plane orientation of the mesogens from the vertically out-of-plane orientation is demonstrated, which is based on comparing the bar width of their interference figures, and by whether they can produce a flash figure upon a small angle rotation of the film. The liquid crystalline film is identified as positive and uniaxial anisotropy after annealing of the perpendicularly irradiated film.
Authors:
J Liu; M Wang; M Dong; L Gao; J Tian
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-9-13
Journal Detail:
Title:  Journal of microscopy     Volume:  -     ISSN:  1365-2818     ISO Abbreviation:  -     Publication Date:  2011 Sep 
Date Detail:
Created Date:  2011-9-13     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0204522     Medline TA:  J Microsc     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
© 2011 The Authors Journal of Microscopy © 2011 Royal Microscopical Society.
Affiliation:
State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang, China.
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