Optical detection of anchoring at free and fluid surfaces using a nematic liquid crystal sensor

Polarizing micrographs of the free and fluid surfaces in contact with nematic liquid crystals were collected and compared with simulated textures to quantitatively understand surface anchoring direction and strength. Wells with square cross section and an open upper surface were filled with a nematic liquid crystal, and free energy calculations were performed to determine the existing structures and their corresponding simulated optical textures. Homeotropic, uniform planar, and degenerate planar anchorings were differentiated based on comparisons with simulations, and surface anchoring strength was estimated. © 2007 American Institute of Physics