Dielectric studies on binary mixtures of systems exhibiting intermediate nematic phase

Two binary phase diagrams of the liquid crystals (4-n-pentylphenyl-4-n-hexyloxybenzoate (PPHB) with 4-nitrophenyl-4-n-pentylbenzoate (NPPB) and 4-n-hexyloxyphenyl-4-n-decyloxybenzoate (HPDB) with NPPB) have been studied. PPHB shows only a nematic phase where as for HPDB trimorphism, with the SmC, SmA and nematic phases, was observed. Substance NPPB which has a strong polar nitro group is non-mesogenic one. Both the phase diagrams show an induction and stabilization of SmA phase and appearance of the nematic state in the high concentration range of polar component. The dielectric measurements confirm the phase transition temperatures and show changes in the short range interaction at the phase transitions.