Photo-induced in-plane alignment of LC molecules on layer-by-layer self-assembled films containing azo dyes evaluated by attenuated total reflection measurements

The photo-induced in-plane alignment of nematic liquid crystal (LC) molecules, 5CB, has been investigated in a cell prepared with alternate layer-by-layer self-assembly of polyelectrolyte and low-molecular weight azobenzene dye films on gold electrodes using the attenuated total reflection (ATR) measurement method. The ATR properties due to excitation of surface plasmon polaritons were observed in the LC cell. They sensitively changed with irradiation of linearly polarized visible light. The experimental results corresponded well with the calculated ATR curves at different polarization states. We have demonstrated that in-plane alignment of the LC molecules on the self-assembled films could also be controlled by the polarization direction of irradiated visible light on the LC cell.