8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

P3.16Fri 911:10-14:00Instability patterns in thin nematic films: comparisonbetween theory and experimentOksana Manyuhina, 1 Anne-Marie Cazabat, 1 and Martine Ben Amar 11 Ecole Normale Superieure, 24 rue Lhomond, 75005, Paris, FranceRecent experimental observations suggest that thin nematic films spread on liquid substratesexhibit periodically deformed long-wavelength pattern (stripes) up to the thickness of twentynanometers [1]. The periodicity of stripes is controlled by the thickness of nematic film ina non-trivial way. Although being extensively studied in the last two decades [2], these newobservations cannot be explained completely by the existing theories. Within the linear stabilityanalysis in the framework of elastic theory of liquid crystals we reconsider the onset of stripeinstability. Considering only the saddle-splay surface term, turns out to be insufficient to identifya finite wavelength for stripes at the lower and the upper thresholds. Comparing theoreticalpredictions with experimental observations, we establish the utility of surface-like term such as anazimuthal anchoring [3].[1] U. Delabre, C. Richard, G. Guéna, J. Meunier, and A. -M. Cazabat, Langmuir 24,3998, 2008; U. Delabre, C. Richard, and A. -M. Cazabat, J. Phys. Chem. B 113, 3647, 2009.[2] O. D. Lavrentovich and V. M. Pergamenshchik, Phys. Rev. Lett. 73, 979, 1994; A. Sparavigna,O. D. Lavrentovich and A. Strigazzi, Phys. Rev. E 249, 1344–1352, 1994.[3] O. V. Manyuhina, A. -M. Cazabat, and M. Ben Amar, Europhys. Lett. 92, 16005, 2010.16