Controlled formation of topological defects of liquid crystals in micro-wells

Abstract

ABSTRACT Topological defects in liquid crystals (LCs) have drawn attention because they frequently control their collective structure and motion. We have developed a robust and straightforward methodology to prepare well-organised isolated topological defects using the fabrication of micro-well structures. We could prepare multiple topological surface defects in each micro-well with high reproducibility. The micro-wells were prepared by capping a glass substrate on micro-molded polydimethylsiloxane (PDMS). The topological defects were stabilised by optimising the size and the shape and satisfying the boundary conditions inside each micro-well, which was controlled by the air-plasma treatment on the surfaces. We found the optimal conditions for the reproducible and stable formation of topological defects; a circular shape with its diameter <10 μm and the glass surface was treated by air-plasma, providing a proper balance of the elastic force to form topological defect at the centre.