title: Use of topological defects as templates to direct assembly of colloidal particles at nematic interfaces.
abstract: In this work, we experimentally investigate the ability of topological defects to guide interfacial assembly of spherical particles with homeotropic anchoring confined to nematic interfaces. We propose two different systems: In the first one, particles are trapped at an air/nematic interface where they spontaneously form various 2D patterns. We demonstrate that the phase transition between these patterns can be controlled by defects formed in the nematic bulk. In the second system, we explore the behavior of particles at the surface of bipolar nematic drops. We found that particles assemble into linear chains and interact with surface defects at the North and South poles of the drop, giving rise to the formation of star structures in a self-assembly process. We detail the mechanism that guides the behavior of particles and discuss the role of defects in the formation of the observed patterns.
authors.affiliation: Laboratoire Charles Coulomb (L2C), UMR5221 CNRS and Université Montpellier 2, Place Eugène Bataillon, 34095 Montpellier, France; Department of Physics and Astronomy, University of Pennsylvania, 209 S. 33rd Street, Philadelphia, PA 19104, USA. Electronic address: mgharbi@sas.upenn.edu.
authors.forename: Mohamed Amine
authors.initials: MA
authors.lastname: Gharbi
authors.affiliation: Laboratoire Charles Coulomb (L2C), UMR5221 CNRS and Université Montpellier 2, Place Eugène Bataillon, 34095 Montpellier, France.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Nobili
authors.affiliation: Laboratoire Charles Coulomb (L2C), UMR5221 CNRS and Université Montpellier 2, Place Eugène Bataillon, 34095 Montpellier, France. Electronic address: christophe.blanc02@univ-montp2.fr.
authors.forename: Christophe
authors.initials: C
authors.lastname: Blanc
keywords: Colloids; Nematic droplets; Nematic interface; Self-assembly; Topological defects