SPIRALS IN CHOLESTERIC LIQUID-CRYSTALS - A POSSIBLE NUCLEATION INITIATOR

The helicoidal structure of the cholesteric liquid crystal phase can b e untwisted by the electric field effect. We have shown that spiral-sh aped structures' could nucleate at the threshold of the field-induced homeotropic state from filaments (linked to the twisted state) embedde d in a homeotropic matrix (untwisted cholesteric). In this article, we describe and study what are the mechanisms involved in this phenomeno n. In particular, we study to what extent the characteristics suggest a nucleation mechanism based on the propagation from the surfaces of d istortions in the distribution of molecules director. These deformatio ns propagate through the homeotropic matrix adjacent to the filaments.