(729e) Asymmetric Nanoparticle Interaction with Nematic Liquid Crystals

The anisotropic optical properties of nematic liquid crystals (LC) make them a popular material for display technology. When introducing particles to the LC system, distortions in the long-range order created by the LC molecules, as well as shape dependent orientation of the particles has brought great interest in potential uses for controlled soft matter systems. Spherical particles were of the first to be studied where these director disruptions were dependent on size, surface anchoring, and the elastic properties of the LC. Following studies found geometric-dependent orientation of particles in LC determined by the odd or even number of edges, however, there are limited studies of asymmetric shape particles. Notable research in living liquid crystals observes the controlled interactions and orientations of bacterial swimmers in LC cells, however the LC system is restricted by biocompatibility and little is understood on whether the shape or mobility of the bacteria have dominating factors in the results. This work focuses on the interactions of synthetic asymmetric particles within a LC cell with varying direction in the long-range order. Due to the birefringence properties of the LC, polarized microscope is used to determine changes in the deformation of the LC field induced by asymmetric particles. Changes in the LC director are created by surface treatment of the liquid crystal cell, creating a planar anchoring cell where the LC molecules align completely parallel to both cell surfaces and a hybrid cell where the LC are parallel to the bottom surface and perpendicular to the top. Observed “butterfly” patterns in the distortion of the LC medium were formed by tadpole shaped particles made up of gold nanospheres coated in silica within the hybrid cell. Disclination loops were also discovered to trail the particles in both cell conditions of varying sizes across samples. Ultimately, the formed distorted LC field will be expected to motivate anisotropic motion of the tadpole particle under external stimuli.