Eur. Phys. J. B 12, 541-546 (1999)
https://doi.org/10.1007/s100510051036

A biaxial nematic gel phase in aqueous vanadium pentoxide suspensions

¹ Laboratoire de Physique des Solides (UMR 8502) , Bâtiment 510, Université Paris-Sud, 91405 Orsay Cedex, France
² Laboratoire pour l'Utilisation du Rayonnement Électromagnétique (UMR 130) , Université Paris-Sud, 91405 Orsay Cedex, France
³ ESRF, B.P. 220, 38043 Grenoble Cedex, France
⁴ Laboratoire de Chimie de la Matière Condensée (URA 1466) , Université Pierre et Marie Curie, 4 Place Jussieu, 75252 Paris, France

Received: 26 May 1999
Published online: 13 August 2012

Abstract

Aqueous suspensions of V₂O₅ ribbons are one of the very few examples of mineral liquid crystals. In the concentrated regime, we show that these ribbons organize in a biaxial nematic gel phase. A Couette shear cell was used to produce a well oriented sample for in situ synchrotron X-ray scattering studies. We observed two perpendicular anisotropic sections of reciprocal space, which proves the biaxial symmetry of the nematic order. The thermodynamic and flow properties of the biaxial nematic are well described by hard-core theories. We suggest the use of a shear geometry to produce and investigate single domains of other biaxial nematics, reported but still questioned in the literature.