| Colloidal particles dispersed in nematic liquid crystals (NLC), whose surface induces parallel alignment of the nematic molecules, induce the nucleation of surface defects called "boojums", which results in distortions in the nematic field with a quadrupolar symmetry. At short distances, surface defects start to interact directly and deviation from the quadrupolar interaction is observed. Recently, it has been shown that the core of boojums can exhibit some complex structure, and can undergo a structural transition when two colloidal particles are closely interacting. For close enough distances, and when the particles are aligned parallel to the far field director, the inner boojums will connect both particles, binding them together. This "bonded" configuration has been reported also in colloidal particles in cholesteric LC. Experiments have shown that the interaction between two spherical micron-sized particles dispersed in a NLC changes significantly when particles are close to a surface or confined in a narrow cell. Here we will present a numerical study on the stability of the bonded configuration, in the Landau-de Gennes framework. In particular, we will show how this configuration is affected by the presence of a planar and curved wall, and under confinement. Authers: Z. Eskandari, N. M. Silvestre and M. M. Telo da Gama |
|