Textural transformations in islands on free standing smectic-C* liquid crystal films

We report on and analyze the textural transformations in islands, thicker circular domains, floating in very thin free standing chiral Smectic-C* liquid crystal films. As an island is growing, an initial pure bend texture of the director changes into a reversing spiral at a critical size. Another distinct spiral texture is induced by changing the boundary condition at the central point defect in the island. To understand these transformations from a pure bend island, a linear stability analysis of the c-director free energy is developed, which predicts a state diagram for the island. Our observations are consistent with the theoretical phase diagram.