Title:	Biaxial smectic A phase in homologous series of compounds composed of highly polar unsymmetrically substituted bent-core molecules
Authors:	Sadashiva, B.K. Reddy, Amaranatha R. Pratibha, R. Madhusudana, N.V.
Issue Date:	2002
Publisher:	Royal Society of Chemistry
Citation:	Journal of Materials Chemistry, 2002, Vol.12, p943 - 950
Abstract:	Several compounds belonging to three new series of five-ring banana-shaped esters, which are unsymmetrically substituted with respect to the central phenyl ring, have been synthesised. One of the arms of these bent-core molecules has been terminally substituted with a highly polar cyano group while the other end contains an alkoxy chain. The mesophases exhibited by these compounds have been characterised using a combination of optical polarising microscopy, differential scanning calorimetry and X-ray diffraction studies. These studies indicate that most of the compounds show two smectic A mesophases which have a partial bilayer ordering. Conoscopic experiments clearly reveal that the lower temperature smectic A phase is biaxial in nature. A structural model has been proposed for the lower temperature biaxial smectic A phase. It is argued that quartets of molecules, which are conducive to the formation of the biaxial phase, can form in the layers. The in-layer birefringence of the biaxial smectic A phase has also been measured as a function of temperature for one of the compounds.
Description:	Restricted Access.
URI:	http://hdl.handle.net/2289/3170
ISSN:	0959-9428 1364-5501 (Online)
Alternative Location:	http://dx.doi.org/10.1039/b109546c
Copyright:	2002 Royal Society of Chemistry
Appears in Collections:	Research Papers (SCM)

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