Abstract
We have measured the azimuthal anchoring strength of liquid crystal molecules in contact with poly[4,4'-oxydiphenylen-1,2,3,4-cyclobutanetetracarboxyimide] (CBDA-ODA) films. The measurement was performed for) a 10 nm-thick film exposed to linearly polarized ultraviolet light (LPUVL) of wavelength 〜250 nm at I J/cm^2 as well as for a rubbed film with the same film thickness. Tile infrared (IR) dichroic difference of the phenyl C-C stretching vibration of CBDA-ODA was almost the same for both films. However, the azimuthal anchoring strength for the LPUVI-exposed film was about 5 times smaller than that for the rubbed film. We believe that the small anchoring strength of the LPUVL-exposed film is due to the decrease of the molecular density and/or the decrease of the polyimide chain length that arise from the photo-induced decomposition. In our presentation. we will also report the relation between the IR dichroism of LPUVL-exposed films and the azimuthal anchoring strength.
