Spectral studies on liquid crystal photoalignment film of photosensitive monomer with fluorinated groups

2, 2, 3, 3, 4, 4-hexafluoro-1, 5-pentanediol dicinnamate ester, which could be crosslinked under irradiation of linearly polarized ultraviolet light, was synthesized in the present work. UV-Visible spectra and FTIR spectra revealed that [2+2] cycloaddition was the main reaction of the monomer, but there was no clear morphological anisotropy on the surface of the obtained photoalignment film through atomic force microscopic analysis. The photoalignment film could induce homogenous alignment of liquid crystal and the alignment is uniform. It was found that the pretilt angle of the photoalignment film is 1 degrees-2 degrees.