Thermal stability of magnetically-aligned nematic liquid crystal layer on nonrubbed polyimide surface

We have studied the thermal stability of liquid crystal (LC) molecules adsorbed on two different polyimide films. LC molecules adsorbed on the polymide film with a high polarity show higher thermal stability than those adsorbed on the polyimide film with a lon polarity. This result is strongly related to the nematic wetting property of the polyimide films; the polyimide film that shows high wettability of the nematic phase gives high thermal stability of LC molecules adsorbed on the film. The result is also analyzed using a two-dimensional rotation diffusion model, and the importance of the nematic setting property for the thermal stability is emphasized in relation to the surface LC ordering.