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Orientation of the Main Chain in Liquid‐Crystalline Side‐Chain Polyesters with Variation of Main‐Chain Spacer Length
Author(s) -
Hempel Günter,
Dimitrova Albena,
Lindau Jürgen,
Reichert Detlef,
Schneider Horst
Publication year - 2003
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.200390036
Subject(s) - chain (unit) , side chain , perpendicular , crystallography , polyester , order (exchange) , materials science , chemistry , orientation (vector space) , polymer , geometry , mathematics , physics , composite material , finance , astronomy , economics
Previous X‐ray investigations on liquid‐crystalline side chain polyesters with variable spacer length in the side chain as well as in the main chain led to the assumption that the structure will change qualitatively if the main chain spacer length exceeds a certain value. We obtained indications supporting this assumption by applying two‐dimensional 13 C NMR. It was shown that for a sample with main chain spacer shorter than the critical length, the main chain segments align perpendicular to the side chains (〈 P 2 〉 = −0.46), and for spacer length larger than critical length, the main chain segments preferentially orient themselves parallel to the side chain (〈 P 2 〉 = 0.28).Visualization of the main‐chain order as revealed by the values of Table 2. The opening angle of the cones corresponds to the average angle of deviation as defined in the text.