Surface 2$\pi$-walls in polar free-standing smectic films

It was found that electric field in free-standing smectic films at high temperature leads to formation of unusual $2\pi$-walls, with quite different structure from the structure of classical $2\pi$-walls. The walls are formed by the change of molecular orientation not only along the film plane (as in usual walls) but also in smectic layers between two surfaces of the film. These walls are nuclei of surface field-induced synclinic-anticlinic transition between states with transverse and longitudinal electric polarization.