LAYER THINNING TRANSITION ABOVE THE BULK SMECTIC-A-ISOTROPIC TRANSITION IN FREESTANDING LIQUID-CRYSTAL FILMS

Upon increasing temperature, high-resolution optical reflectivity data have revealed unusual melting transitions above the smectic-A-isotrop ic transition in free-standing films of one partially perfluorinated c ompound. For sufficiently thin films (fewer than nine layers), a seque nce of regular layer-by-layer thinning transitions is found. The evolu tion of this unique thinning process can be well described by a simple power law with exponent zeta = 0.70.