Interactions of micro-rods in a thin layer of a nematic liquid crystal

We present an experimental analysis of the topological properties of a nematic liquid crystal in the vicinity of small cylindrical objects (micro-rods), dispersed in the nematic liquid crystal 5CB (4-n-pentyl-4-cyanobiphenyl). Depending on the type of liquid crystal anchoring on the surfaces of micro-rods, we have observed two types of the symmetry in the surrounding liquid crystal molecules: dipolar and quadrupolar. Using the manipulation of micro-rods with laser tweezers, the strength and separation dependencies of various pair interaction potentials have been determined. Our results are in qualitative agreement with previous theoretical predictions for 2D interactions of micro-rods in the nematic liquid crystals.