Photosensitive monomers of bisphenol A dieinnamic ester and hexafluorobiphenol A dicinnamate ester were used for preparation of films by photo-crosslinking reaction initiated by irradiation of linearly polarized uhraviolet light．Homogeneous and homeotropic alignments of molecules of a nematic liquid crystal 5CB were obtained on the two resultant films respectively The structure change due to the photo-erosslinking reaction process was revealed by Fourier transform infrared spectra．The surface of these fihns didn’t show clear morphological anisotropy through atomic force microscope analysis．It was found that the surface energy

especially its polar componeut of these aligned films decreased with introduction of the fluorine groups．These results indicated that it was the fluorinated groups that caused the homeotmpic alignment of liquid crystal molecules．