Novel atropoisomeric binaphthyl-containing liquid crystalline copolymers forming chiral nematic phases

Autor:	Peter V. Shibaev, Valery Shibaev, Natalia Boiko, Klaus Bechgaard, Kjeld Schaumburg, H.-J. Deussen, A. Yu. Bobrovsky, Thomas Bjørnholm
Rok vydání:	1997
Předmět:	chemistry.chemical_classification Materials science Mesophase General Chemistry Polymer Condensed Matter Physics Crystallography chemistry.chemical_compound Monomer chemistry Liquid crystal Copolymer Organic chemistry General Materials Science Pendant group Glass transition Chirality (chemistry)
Zdroj:	Liquid Crystals. 22:451-457
ISSN:	1366-5855 0267-8292
DOI:	10.1080/026782997209162
Popis:	Novel liquid crystalline (LC) acrylate side group copolymers, which consist of nematogenic phenyl 4-methoxybenzoate acrylate monomer (A) and novel chiral binaphthyl (BN) methacrylate monomers (MB-n) have been synthesized. The copolymers prepared differ in the spacer lengths of MB-n (n 3,5,11) and in their compositions. The homopolymers of the three new chiral binaphthyl monomers MB-n were also prepared. Copolymers with a low concentration of binaphthyl monomer units (less than 16 mol%) display a cholesteric mesophase. The induced chirality in the polymers is due to atropoisomerism (C2-symmetry) of the molecules. The helical twisting powers (beta), caused by the atropoisomeric units in the synthesized copolymers, were determined, and their temperature dependencies studied. The unusually high negative temperature coefficient of beta observed above the glass transition temperature is explained in terms of conformational changes of the BN molecules in the copolymers.
Databáze:	OpenAIRE
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