Reconfigurable assembly of topological defects in smectic liquid crystals confined at 3D-printed curved surfaces

The fabrication of assembled structures of topological defects in liquid crystals has attracted a lot of attention during the last decade. This interest stems from the potential of these defects in a wide range of technological applications, including in the field of nanotechnology. Different techniques can be employed to create large areas of engineered defects in liquid crystals. Some of them include the use of mechanical shearing, chemical surface treatment, external fields, or geometric confinement. The technique of 3D printing has recently emerged as a new powerful method to fabricate novel patterning topographies that other microfabrication techniques cannot make. In particular, the creation of confining substrates with curved topographies. In this work, we show the advantages of using 3D-printed curved surfaces to confine smectic liquid crystals and engineer new structures of topological defects [1,2]. Additionally, we demonstrate the ability of these defects to act as a scaffold for assembling nanomaterials [2]. We also discuss the limitations of this approach and explain the relationship between the spontaneous assembly of defects and the concentration of dispersed nanomaterials.