Mesophase behaviour of binary mixtures of bent-core and calamitic compounds

Cvetinov, M. and Obadović, D. and Stojanović, M. and Lazar, D. and Vajda, Anikó and Éber, Nándor and Fodor-Csorba, Katalin and Ristić, I. (2013) Mesophase behaviour of binary mixtures of bent-core and calamitic compounds. LIQUID CRYSTALS, 40 (11). pp. 1512-1519. ISSN 0267-8292

Preview

Text 1407.7992v1.pdf Available under License Creative Commons Attribution. Download (703kB) | Preview

Abstract

The mesophase behaviour of binary mixtures of bent-core and calamitic liquid crystals is presented. The nematogenic 4,6-dichloro-1,3-phenylene bis[4’-(10-undecen-1-yloxy)-1,1’- biphenyl-4-carboxylate] (I) was the banana-shaped component. As the calamitic compound ethyl 4’-(9-decen-1-yloxy)-1,1’-biphenyl-4-carboxylate (II), similar to one arm of the bent- core molecule, was used which exhibits smectic phases in a wide temperature range. A total of 6 mixtures with different compositions were prepared and studied by polarising optical microscopy, differential scanning calorimetry and X-ray diffraction on non-oriented samples. In the mixtures a nematic phase is not concomitant with smectic A phase, and the temperature range of both phases highly depends on the concentration of the comprising compounds. Lowered melting temperatures have been observed for all mixtures with respect to that of the pure compounds. Unforeseen finding is the induction of a monotropic SmC phase in mixtures with lowest concentration of the bent-core compound. Semi-empirical quantum-chemical calculations have also been performed. Based on the calculated molecular conformation, as well as on collected X-ray diffraction data, a model for a possible self- assembly of the banana-shaped and calamitic compounds is proposed.

Actions (login required)

Edit Item