Abstract
The biaxial nematic liquid crystalline phase was predicted several decades ago. Several vigorous attempts to find it in various systems resulted in mis-identifications. The results of X-ray diffraction and optical texture studies of the phases exhibited by rigid bent-core molecules derived from 2,5-bis-(p-hydroxyphenyl)-l,3,4-oxadiazole reveal that the biaxial nematic phase is formed by three compounds of this type. X-ray diffraction studies reveal that the nematic phase of these compounds has the achiral symmetry D2h, in which the overall long axes of the molecules are oriented parallel to each other to define the major axis of the biaxial phase. The apex of the bent-cores defines the minor axis of this phase along which the planes containing the bent-cores of neighboring molecules are oriented parallel to each other.
Similar content being viewed by others
References
P de Gennes,Physics of liquid crystals (Clarendon, Oxford, 1974)
M J Freiser,Phys. Rev. Lett. 24, 1041 (1970)
L J Yu and A Saupe,Phys. Rev. Lett. 45, 1000 (1980)
A Saupe, P Boonbrahm and L J Yu,J. Chem. Phys. 80, 7 (1983)
R Alben,J. Chem. Phys. 59, 4299 (1973);Phys. Rev. Lett. 30, 778 (1973)
D W Allender, M A Lee and N Hafiz,Mol. Cryst. Liq. Cryst. 124, 45 (1985)
S Chandrasekhar, V N Raja and B K Sadashiva,Mol. Cryst. Liq. Cryst. Lett. Sect. 7, 65 (1990)
J Malthele, L Liebert, A-M Levelut and Y Galerne,C. R. Acad. Sci. Paris 303, 1073 (1986)
IG Shenouda, Y Shi and M Neubert,Mol. Cryst. Liq. Cryst. 257, 209 (1994)
J Hughes, G Kothe, G R Luckhurst, J Malthete, M E Neubert, I Shenouda, B A Timimi and M Tittlebach,J. Chem. Phys. 107, 9252 (1997)
T Nioriet al, J. Mater. Chem. 6, 1231 (1996)
D R Linket al, Science 278, 1924 (1997)
G Heppkeet al, Phys. Rev. E60, 5575 (1999)
G Pelzlet al, Adv. Mater. 11, 707 (1999)
V L Lorman and B Mettout,Phys. Rev. Lett. 82, 940 (1999)
P Tolédanoet al, Phys. Rev. E62, 5143 (2000)
A Royet al, Phys. Rev. Lett. 82, 1466 (1999)
G R Luckhurst,Thin Solid Films 393, 40 (2000)
T J Dingemans and E T Samulski,Liq. Cryst. 27, 131 (2000)
S Chandrasekharet al, Mol. Cryst. Liq. Cryst. 288, 7 (1996)
A Primak, M Fisch and S Kumar,Phys. Rev. Lett. 88, 035701 (2002)
WL McMillan,Phys. Rev. A5, 1673 (1973)
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Acharya, B.R., Primak, A., Dingemans, T.J. et al. The elusive thermotropic biaxial nematic phase in rigid bent-core molecules. Pramana - J Phys 61, 231–237 (2003). https://doi.org/10.1007/BF02708305
Issue Date:
DOI: https://doi.org/10.1007/BF02708305