Effects of pretilt angle and anchoring energy on alignment of uniformly lying helix mode

Abstract

We investigated the effects of pretilt angle and anchoring energy on the formation of a uniformly lying helix (ULH) texture of cholesteric liquid crystals (CLCs). Pretilt angle was controlled by the thickness of a vertical alignment layer coated onto a planar alignment layer. In the given pretilt angle, the anchoring energy was enhanced by introducing reactive mesogen to the vertical alignment material. To characterise quantitatively the formation of the ULH texture we introduced reflectance, governed by areas of the ULH region and the planar-aligned CLC region. We found that the ULH texture was more widely formed under the condition of higher pretilt angle and weaker anchoring energy. Also, a more uniform alignment of the ULH texture was achieved with the higher pretilt angle even under the same anchoring energy condition.