Dimorphism SmA-B2 in bent-core mesogens with perfluorinated terminal chains

Several banana-shaped liquid crystal materials with perfluorinated terminal chains have been synthesized. A dimorphism SmA-B-2 was proved by X-ray studies and electro-optical measurements. The unusual ratio d/L (d = layer spacing, L = molecular length) and the unexpected behaviour of the layer spacing at the phase transition SmA --> B-2 can be interpreted by a change of the packing of the bent molecules.