Orientational quenched disorder of a nematic liquid crystal.
By means of direct imaging, we map the surface heterogeneities of the nematic director orientation on a SiOx anchoring layer. The spatial correlations of surface director orientations are well fitted with a compressed exponential with exponent of 1.5 and typical correlation length of few microns. To discuss these results a formal analogy is established between the equation governing the nematic surface torques and the Langevin equation. Based on this analogy we prove that the disorder is spatially correlated orientational quenched disorder. The measured correlation length is discussed in terms of substrate morphology and molecular adsorption.
Nespoulous
Mathieu
M
Laboratoire des Colloïdes, Verres et Nanomatériaux, Université Montpellier II, Place Eugène Bataillon, 34090 Montpellier, France.
Blanc
Christophe
C
Nobili
Maurizio
M