Cellular solid behaviour of liquid crystal colloids. 2. Mechanical properties
Abstract
This paper presents the results of a rheological study of thermotropic nematic colloids aggregated into cellular structures. Small sterically stabilised PMMA particles dispersed in a liquid crystal matrix densely pack on cell interfaces, but reversibly mix with the matrix when the system is heated above Tni. We obtain a remarkably high elastic modulus, G'~10^5 Pa, which is a nearly linear function of particle concentration. A characteristic yield stress is required to disrupt the continuity of cellular structure and liquify the response. The colloid aggregation in a ``poor nematic'' MBBA has the same cellular morphology as in the ``good nematic'' 5CB, but the elastic strength is at least an order of magnitude lower. These findings are supported by theoretical arguments based on the high surface tension interfaces of a foam-like cellular system, taking into account the local melting of nematic liquid and the depletion locking of packed particles on interfaces.
Cite
@article{arxiv.cond-mat/0005080,
title = {Cellular solid behaviour of liquid crystal colloids. 2. Mechanical properties},
author = {V. J. Anderson and E. M. Terentjev},
journal= {arXiv preprint arXiv:cond-mat/0005080},
year = {2009}
}
Comments
Latex 2e (EPJ style) EPS figures included (poor quality to comply with space limitations)