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Does Shear-Flow Enhance or Suppress Fluctuations in Shectics?

Published online by Cambridge University Press:  25 February 2011

R. Bruinska  and
Y. Rabin
R. Bruinska
Affiliation:
Physics Department, University of California, Los Angeles, CA 90024
Y. Rabin
Affiliation:
Physics Department, Bar Ilan University, Ramat-Gan S2900, Israel
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Abstract

We investigate the effects of shear-flow on the smectic phase of thermotropic and lyotropic liquid crystals. We show that shear-flow transforms a Smectic-A thermotropic into an orthorombic solid by the suppression of undulation fluctuations. In contrast, the lyotropic Lα phase exhibits, in addition, a very striking enhancement of shortwavelength concentration fluctuations - a phenomenon which is closely analogous to a well-known effect in polymer solutions. We demonstrate this result using both hydrodynamic theory as well as a microscopic model based on the Helfrich theory of membranes. The dispersion relation of the concentration fluctuations is in qualitative agreement with recent experiments on the Lα phase in shear flow.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 248: Symposium O – Complex Fluids , 1991 , 185
Copyright
Copyright © Materials Research Society 1992

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