Europhys. Lett.
Volume 70, Number 1, April 2005
Page(s) 95 - 101
Section Condensed matter: structural, mechanical and thermal properties
Published online 09 March 2005
Europhys. Lett., 70 (1), pp. 95-101 (2005)
DOI: 10.1209/epl/i2004-10455-3

Effective pair interactions between colloidal particles at a nematic-isotropic interface

D. Andrienko1, M. Tasinkevych2, 3 and S. Dietrich2, 3

1  Max-Planck-Institut für Polymerforschung - Ackermannweg 10 55128 Mainz, Germany
2  Max-Planck-Institut für Metallforschung - Heisenbergstr. 3 70569 Stuttgart, Germany
3  Institut für Theoretische und Angewandte Physik, Universität Stuttgart Pfaffenwalding 57, 70569 Stuttgart, Germany

received 9 December 2004; accepted in final form 31 January 2005
published online 9 March 2005

The Landau-de Gennes free energy is used to study theoretically the interaction of parallel cylindrical colloidal particles trapped at a nematic-isotropic interface. We find that the effective interaction potential is non-monotonic. The corresponding force-distance curves exhibit jumps and hysteresis upon approach/separation due to the creation/annihilation of topological defects. Minimization results suggest a simple empirical pair potential for the effective colloid-colloid interaction at the interface. We propose that the interface-mediated interaction can play an important role in self-organization and clustering of colloidal particles at such interfaces.

61.30.Dk - Continuum models and theories of liquid crystal structure.
82.70.Dd - Colloids.
61.30.Jf - Defects in liquid crystals.

© EDP Sciences 2005