Periodic structures on liquid-phase smectic A, nematic and isotropic free surfaces.

The free boundary of smectic A (SmA), nematic and isotropic liquid phases were studied using a polarized optical microscope, an interferometric surface structure analyzer (ISSA), an atomic force microscope (AFM) and a scanning near-field optical microscope (SNOM). Images of the SmA phase free surface obtained by the polarized microscope and ISSA are in good correlation and show a well-known focal domain structure. The new periodic stripe structure was observed by scanning near-field optical microscopy on the surface of the smectic A, nematic and isotropic phases.

Nanoprofilometry study of focal conic domain structures in a liquid crystalline free surface.

This work presents the first high-resolution nanoprofilometry study consisting of nanoscale resolution surface profile measurements and high-quality visualization of a the free surface of a liquid crystal-air boundary. The capabilities of this new experimental method, as applied for liquid crystal free boundaries, are discussed. The formation of focal conic domain structures at the smectic-A-air free boundary was detected and studied.