NOVEL BIAXIAL BILAYERED FLUID MESOPHASES

In a substance with a substituted chlorine on the central ring of an alkylphenyl cyanobenzoyloxybenzoate evidence is obtained in a biaxial fluid medium for anomalies of periodicity similar to those initially found in the nematic and smectic A phases of the unsubstituted series ( ″DB//n″ ). From X-ray studies, microscopic observations, D. S. C. recordings and magnetic measurements, a new mesomorphic nematic-smectic A//2 -smectic C//2 -smectic//? sequence is reported. In the three smectic modifications there is a liquid-like order within the layers (even at short-range) and the layer thickness is close to two molecular lengths. The lowest temperature smectic phase seems to be a new lamellar structure with well defined layers.