Two-stage crystallization on the surface of smectic nanofilms

The influence of the surface and finite size on crystallization in nanofilms of a smectic C liquid crystal with thicknesses between two and several tens of molecular layers has been studied. Transitions in a single surface molecular layer have been detected by optical methods. It has been found that transitions on the film surface take place at a temperature $8{}^\circ$C higher than the crystallization temperature in a bulk sample. Two-stage crystallization has been detected in surface layers where the surface induces a transition to an intermediate structure different from the structure of the phases of the bulk sample.