Measurement of polar anchoring coefficient for nematic cell with high pretilt angle

A method to determine the surface anchoring energy of a nematic liquid crystal is proposed. The technique implies the measurements of optical retardation of a nematic cell as a function of a strength and direction of the applied magnetic field. It enables one to get both pretilt angle α and anchoring coefficient Wa in the course of the same experiment. As an example, both parameters (α=10.9° and Wa=1.5×10−5 J/m2) are measured at the interface between the nematic 5CB and rubbed polyimide film.