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Cellular solid behaviour of liquid crystal colloids. 2. Mechanical properties

V. J. Anderson·E. M. Terentjev
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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.

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V. J. Anderson, E. M. Terentjev. 2000-05-03. Cellular solid behaviour of liquid crystal colloids. 2. Mechanical properties. https://doi.org/10.1007/s101890170138

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