Eur. Phys. J. E 4, 11-20

Cellular solid behaviour of liquid crystal colloids 1. Phase separation and morphology

V.J. Anderson¹, E.M. Terentjev¹, S.P. Meeker², J. Crain² and W.C.K. Poon².

¹  Cavendish Laboratory, The University of Cambridge, Madingley Road, Cambridge CB3 0HE, UK
²  Department of Physics and Astronomy, The University of Edinburgh, Mayfield Road, Edinburgh EH9 3JZ, UK

emt1000@cus.cam.ac.uk

(Received 13 March 2000 and Received in final form 6 June 2000)

Abstract
We study the phase ordering colloids suspended in a thermotropic nematic liquid crystal below the clearing point and the resulting aggregated structure. Small (150 nm) PMMA particles are dispersed in a classical liquid crystal matrix, 5CB or MBBA. With the help of confocal microscopy we show that small colloid particles densely aggregate on thin interfaces surrounding large volumes of clean nematic liquid, thus forming an open cellular structure, with the characteristic size of inversely proportional to the colloid concentration. A simple theoretical model, based on the Landau mean-field treatment, is developed to describe the continuous phase separation and the mechanism of cellular structure formation.

PACS
61.30.-v - Liquid crystals..
82.70.-y - Disperse systems..
64.75.+g - Solubility, segregation and mixing; phase separation..


© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2001