title: Colloidal Particles in Thin Nematic Wetting Films.
abstract: We experimentally and theoretically study the variety of elastic deformations that appear when colloidal inclusions are embedded in thin wetting films of a nematic liquid crystal with hybrid anchoring conditions. In the thickest films, the elastic dipoles formed by particles and their accompanying defects share features with the patterns commonly observed in liquid crystal cells. When the film gets thinner than the particles size, however, the capillary effects strongly modify the appearance of the elastic dipoles and the birefringence patterns. The influence of the film thickness and particles sizes on the patterns has been explored. The main experimental features and the transitions observed at large scale-with respect to the inclusions' size-are explained with a simple two-dimensional Ansatz, combining capillarity and nematic elasticity. In a second step, we discuss the origin of the variety of observed textures. Developing a three-dimensional Landau-de Gennes model at the scale of the particles, we show that the presence of free interfaces and the beads confinement yield metastable configurations that are quenched during the film spreading or the beads trapping at interfaces.
authors.affiliation: Université de Tunis El Manar , Faculté des Sciences de Tunis, LR99ES16 Laboratoire Physique de la Matière Molle et de la Modélisation Electromagnétique, 2092, Tunis, Tunisia.
authors.forename: Haifa
authors.initials: H
authors.lastname: Jeridi
authors.affiliation: Max-Planck-Institut für Intelligente Systeme , Heisenbergstraße 3, D-70569 Stuttgart, Germany.|Institut für Theoretische Physik IV, Universität Stuttgart , Pfaffenwaldring 57, D-70569 Stuttgart, Germany.
authors.forename: Mykola
authors.initials: M
authors.lastname: Tasinkevych
authors.affiliation: Université de Tunis El Manar , Faculté des Sciences de Tunis, LR99ES16 Laboratoire Physique de la Matière Molle et de la Modélisation Electromagnétique, 2092, Tunis, Tunisia.
authors.forename: Tahar
authors.initials: T
authors.lastname: Othman
authors.affiliation: Laboratoire Charles Coulomb, UMR 5221, CNRS-Université de Montpellier , 34095 Montpellier, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Blanc