2pi and pi walls in antiferroelectric smectic-C*A and smectic-C free-standing films.

We observed, in free-standing films of antiferroelectric liquid crystal, dependence of the wall structure on orientation of walls with respect to the external field direction and on parity of number of smectic layer in the film. These observations are explained by anisotropy of two-dimensional elastic constants and by dependence of polarization direction on parity of the film. Investigations in electric and magnetic field allow us to determine the values of elastic constants and longitudinal polarization of the films.

Collective behavior of light-induced droplets in smectic membranes.

Collective behavior and organization of droplets in thin smectic membranes were investigated using polarized light microscopy. Droplets were nucleated in membranes by light illumination. We observed the formation of periodic hexagonal and square lattice structures from droplets at large droplet concentration.