Eur. Phys. J. E 7, 205-208 (2002)
DOI: 10.1140/epje/i200101182

Rapid Note

Line defect dynamics around a colloidal particle

J.C. Loudet, O. Mondain-Monval and P. Poulin

Centre de Recherche Paul Pascal - CNRS, Avenue A. Schweitzer, 33600 Pessac, France

loudet@crpp.u-bordeaux.fr

(Received 21 December 2001)

Abstract
We study experimentally the dynamics of a topological defect located around a colloidal particle suspended in a thermotropic nematic liquid crystal. The considered defect consists of a disclination loop encircling the particle at the equator. Under specific conditions, it is shown that this disclination continuously shrinks to a hedgehog defect located in the immediate vicinity of the particle. This phenomenon corresponds to a transition between an elastic quadrupolar configuration and an elastic dipolar configuration. We performed a basic numerical calculation to get an estimate of the dissipated energy during the transition; we compare the results with theoretical predictions that describe the elastic energy of particles surrounded by defects.

PACS
61.30.Jf - Defects in liquid crystals.
61.30.Gd - Orientational order of liquid crystals; electric and magnetic field effects on order.


© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2002