Résumé:

Liquid crystal shells offer an elegant way for imprinting well defined interaction sites on a sphere, since a set of symmetrically positioned topological defects naturally decorate the ground states of these systems. These defects are a consequence of a fascinating interplay between topology and energy that arises when an ordered system is confined to a space with curvature. The prospect of using these nematic shells as nano or micro-sized superatoms creates an avenue for the fabrication of new materials with revolutionary technological applications. In this talk, I will show recent advances in the topic. Microfluidic techniques have enabled the experimental realization of nematic shells [1]. A precise control in the defect architecture has been achieved by tuning parameters such as shell thickness, anchoring of the liquid crystal at the boundaries, or the type of liquid crystal phase considered [2-4]. A number of different defect structures have been engineered, including the sp, sp2 and sp3 symmetries of carbon atoms, which have enormous potential for photonic applications [2]. On the other hand, the functionalization of defects with ligands, capable to establish directional bonds between shells, has just started to be explored experimentally. A promising alternative has recently been proposed, consisting in exploiting attractive elastic interactions between defects and small beads embedded in the liquid crystal [5].