New method for measuring polar anchoring energy of nematic liquid crystals

Abstract

A new method for measuring a polar anchoring energy of nematic liquid crystals (LCs) is proposed. A variation of LC tilt angle on the surface with an applied electrical field was determined by a reflective method. The twisted LC cell configuration was selected to compensate a contribution of the induced birefringence in the reflective spectra. The electrical field controlled reflectance was used to analyse the potential form of the polar anchoring energy and to define the anchoring strength. The proposed method is applicable for 2–5 μm thick LC cells.

Keywords:

• anchoring energy
• liquid crystal
• reflective measurements
• surface tilt angle

Acknowledgement

This research was supported by HKUST RGC grant 612406, CERG RPC07/08. EG01 and CERG 612208.