Orientational order of 4′- n-pentyl-4-cyanobiphenyl molecules deposited on azobenzene monolayers

Abstract

Using optical second harmonic generation (SHG) and polarized absorption (PA) measurements, the n-th orientational order parameters S n ( n = 1, 2, 3) of 4′- n-pentyl-4-cyanobiphenyl (5CB) films were determined whilst 5CB molecules were deposited onto silica substrate coated with a trans- or cis-form 6Az10PVA (azobenzene side-chain polymer) monolayer by evaporation method. The experimental results clearly show that the orientational order of 5CB film depends on the form of surface azobenzene monolayer, especially at the beginning of 5CB deposition. It was also found that the orientational order saturates when monolayer of 5CB film is deposited on the azobenzene monolayer.