Two-dimensionally periodic phases in mixtures of compounds made of rodlike and bent-core molecules

Pratibha, R. ; Madhusudana, N. V. ; Sadashiva, B. K. (2005) Two-dimensionally periodic phases in mixtures of compounds made of rodlike and bent-core molecules Physical Review E, 71 (1). 011701_1-011701_12. ISSN 1063-651X

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Official URL: http://pre.aps.org/abstract/PRE/v71/i1/e011701

Related URL: http://dx.doi.org/10.1103/PhysRevE.71.011701

Abstract

We report two distinct types of two-dimensionally periodic phases in different concentration regions of a binary system composed of the bent-core (BC) compound 1,3-phenylene bis[4-(3-methylbenzoyloxy)]4'-n-dodecylbiphenyl 4'-carboxylate (BC12) and the rodlike (R) compound 4-n-octyloxy 4'-cyanobiphenyl (8OCB). BC12 exhibits only the lamellar B2 phase. 8OCB which has a highly polar cyano end group exhibits the smectic-Ad phase with a lamellar structure of partial bilayers made of antiparallel pairs of the polar molecules. The molecular arrangements in the two-dimensionally periodic phases have been deduced based on optical microscopy, polarized infrared and x-ray diffraction studies. The arrangement in the two-dimensionally periodic phase in lower concentration ranges of BC12 (24 to 35 mol%) is dictated by the partial bilayer structure formed by the rods. The BC molecules arrange themselves with their arrow axes parallel to the long axes of the R molecules and the structure conforms to the c2mm space group symmetry. In higher concentration ranges of BC12 (35 to 60 mol%) the structure is dominated by the BC molecules, to form the familiar B1 phase with the p2mg space group symmetry. The R molecules lie at the interfaces of these domains stabilizing the structure.

Item Type:Article
Source:Copyright of this article belongs to American Physical Society.
ID Code:21105
Deposited On:20 Nov 2010 09:09
Last Modified:17 May 2016 05:19

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