On the origin of Grandjean-Cano lines in liquid-crystalline blue phases

Abstract
A model is proposed to explain the Grandjean-Cano lines occurring in wedge-shaped samples of liquid-crystalline blue phases I and II. Between stretched and compressed areas of the cubic BP lattice edge dislocations occur which give rise to the observed Cano lines. The results for the BP I are in agreement with a b.c.c. lattice in (110) orientation parallel to the surface whereas for the BP II a s.c. lattice in (100) orientation was derived.