Probing alignment of liquid crystals on silane derivatives by second harmonic generation

We studied surface second-harmonic generation from thin films of 4'-n-pentyl-4-cyano-biphenyl (5CB) nematic liquid crystal (NLC) deposited onto layers of several silanes dipped on conductive glasses. We also studied a new liquid crystalline polymer deposited onto silanized substrates. The cinnamoyl side groups of this polymer can be aligned by linearly polarized UV light. The average orientation and surface order of the nematic. were determined by Fourier analysis of the reflected and transmitted angular dependent second harmonic signal. The aim was to check the possible use of these materials as a control layer for the anchoring properties of nematics