Magnetic field‐assisted liquid crystal alignment on a solid substrate: drift of easy orientation axis, anchoring energy and angular distribution of adsorbed liquid crystal molecules

Abstract

The anchoring properties of a film of anisotropically adsorbed liquid crystal (LC) molecules on a rigid substrate have been studied. The LC film was prepared by cooling it from the isotropic phase in the presence of a magnetic field parallel to the surface of the substrate. Relationship between the anchoring energy, easy axis direction and angular distribution of the adsorbed molecules, and changes in their angular distribution due to adsorption–desorption, were studied. The dependence of the anchoring energy on the duration and the temperature at which the LC film is annealed allowed an estimation of the activation energy of desorption of LC molecules on ITO surface, ΔE≈0.55 eV. The results suggest that hydrogen bonds are responsible for the adsorption of LC molecules on the substrate.

Acknowledgments

The work was supported by the National Science Foundation* through grant DMR‐0708290, ECO‐NET Project “Ancrage des cristaux liquides sur des polymeres photo‐sensibles pour l'affichage” and by the Korea Research Foundation Grant funded by the Korean Government (MOEHRD, KRF‐2006‐613‐D00004).

Notes

*. Any opinions, findings and conclusions or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.