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Paranematic-to-nematic Ordering of a Binary Mixture of Rod-like Liquid Crystals Confined in Cylindrical Nanochannels by Calus, Sylwia; Jablonska, Beata; Busch, Mark; Rau, Daniel; Huber, Patrick; Kityk, Andriy V. is a scholarly article available to read on EtoBox.

What is Paranematic-to-nematic Ordering of a Binary Mixture of Rod-like Liquid Crystals Confined in Cylindrical Nanochannels about?

We explore the optical birefringence of the nematic binary mixtures 6CB$_{1-x}$7CB$_x$ ($0~\le~x~\le~1$) imbibed into parallel-aligned nanochannels of mesoporous alumina and silica membranes for channel radii of $3.4~\le~R~\le 21.0$ nm. The results are compared with the bulk behavior and analyzed with a Landau-de-Gennes model. Depending on the channel radius the nematic ordering in the cylindrical nanochannels evolves either discontinuously (subcritical regime, nematic ordering field $\sigma<1/2$) or continuously (overcritical regime, $\sigma>1/2$), but in both cases with a characteristic paranematic precursor behavior. The strength of the ordering field, imposed by the channel walls, and the magnitude of quenched disorder varies linearly with the mole fraction $x$ and scales inversely proportionally with $R$ for channel radii larger than 4 nm. The critical pore radius, $R_c$, separating a continuous from a discontinuous paranematic-to-nematic evolution, varies linearly with $x$ and differs negligibly between the silica and alumina membranes. We find no hints of preferred adsorption of one species at the channels walls. By contrast, a linear variation of the nematic-to-paranematic

Author

Calus, Sylwia; Jablonska, Beata; Busch, Mark; Rau, Daniel; Huber, Patrick; Kityk, Andriy V.

Published

2014

Language

EN