New alternative for the smectic-A1-reentrant nematic-smectic-Ad bicritical point

Reentrant orthogonal smectic-A phase below a tilted smectic-C phase in a chiral compound

A reentrant orthogonal smectic-A (SmA) phase below the tilted smectic-C phase is established in a chiral liquid crystalline compound. The temperature evolution of the layer spacing confirms monolayer structure in both SmA phases, the upper SmA as well as the reentrant SmA phase. The reentrancy of the SmA phase is explained on the basis of the mean field free energy taking into account nonmonotoneous temperature dependence of the lowest term coefficient.

Double reentrance of surface arrangements in freestanding liquid crystal films

The molecular arrangement of tilted surface layers on freestanding films above the bulk smectic-A-smectic-C(*) transition has been studied by null transmission ellipsometry. In the presence of an applied in-plane electric field, a synclinic-anticlinic-synclinic-anticlinic double reentrance has been observed. Furthermore, we have characterized a novel transition from the synclinic arrangement to a structure in which the interior layers tilt in the same orientation and the outermost surface layers tilt oppositely with the interior layers.