A. Kilian et A. Sonnet, INFLUENCE OF THE SADDLE-SPLAY ENERGY ON THE STRUCTURE OF CHOLESTERIC LIQUID-CRYSTALS CONFINED TO A CAPILLARY, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics, 52(3), 1995, pp. 2702-2706
We calculate the director field of a cholesteric liquid crystal confin
ed to a capillary. It is assumed to be rotationally symmetric, defect
free, and homogeneous along the capillary axis. The boundary coupling
is either rigid or planar-free. We found that the saddle-splay energy
induces a preferred direction for the director at the capillary wall.
Thus this setup is suitable for high precision measurements of K-24 Si
nce our result holds for capillaries of arbitrary radius, it is a coun
terexample to the standard argument that K-24 can be neglected for geo
metries which are defect free and large enough.