On the Molecular Requirements for the Stabilisation of Thermotropic Biaxial Ordering in Rod-Plate Nematics

• Published in: Molecular crystals and liquid crystals science and technology. Section A, Molecular crystals and liquid crystals Molecular crystals and liquid crystals, 2001-06, Vol.362 (1), p.67-78
• Main Authors: Vanakaras, A. G., Terzis, A. F., Photinos, D. J.
• Format: Article
• Language: English
• Subjects: Biaxial nematics; calamitic; Condensed matter: structure, mechanical and thermal properties; discotic; Exact sciences and technology; interconverting conformations; Liquid crystals; Physics; Structure of solids and liquids; crystallography; Theory and models of liquid crystal structure
• ISSN: 1058-725X
• DOI: 10.1080/10587250108025760

A nematic consisting of rod-like and plate-like molecular species is expected to exhibit phase biaxiality over a range of concentrations. Phase separation, however, prevents the achievement of such concentrations in mixtures of conventional, low molar mass, thermotropic calamitic and discotic mesogens. We present a theoretical study of the molecular requirements for phase biaxiality in three types of rod-plate nematics, namely in (i) binary mixtures of hard rods and discs, (ii) mixtures of rods and discs exhibiting molecular association, either by direct rod-disc interaction or through selective interactions with a third molecular species and (iii) single component systems with interconverting rod-like and plate-like conformations.