Measurements of the azimuthal anchoring energy at a polyimide-nematic interface with a new transmitted light method

A new transmitted light method has been used to measure the azimuthal anchoring energy coefficientWat the interface between the nematic liquid crystal 5CB and a rubbed polyimide substrate. This method overcomes the typical drawbacks of the transmitted light methods and provides an unambiguous measurement of the director rotation at the surface. The contributions of the bulk director distortion are very small and can be easily separated from those due to the anchoring. The measurements can be performed also in the critical case of somewhat strong anchoring. The small optical anisotropy of the orienting layer (polyimide)can be also taken into account.