Unwinding of the uniform lying helix structure in cholesteric liquid crystals next to a spatially uniform aligning surface

Journal article

The symmetry of the cholesteric uniform lying helix (ULH) structure, where the helix axis is aligned in a single direction parallel to the device substrates, is not compatible with a uniform surface alignment and an unwinding of the helical structure is expected at the interface. Fluorescence confocal polarizing microscopy experiments are performed on the interface between a bulk ULH and a uniform aligning surface (for both planar and homeotropic alignments). The results are analyzed in the framework of a finite difference numerical simulation based on the Frank elastic distortion, to determine relevant director structures. An optical model is introduced to predict three-dimensional fluorescence profiles for the structures. Comparison of experimental and theoretical results shows that the equilibrium structure of the system involves a continuous unwinding of the helix close to the surface. © 2009 The American Physical Society.

Authors: Salter, P; Carbone, G; Jewell, SA; Elston, S; Raynes, P

• Publication status: Published
• Journal: PHYSICAL REVIEW E
• Volume: 80
• Issue: 4
• Publication date: 2009-10-01
• DOI: 10.1103/PhysRevE.80.041707
• EISSN: 1550-2376
• ISSN: 1539-3755
• Language: English
• Keywords: liquid theory; cholesteric liquid crystals; finite difference methods; liquid structure; fluorescence