Density and ultrasonic velocity measurements in hexyloxybenzylidene phenylazoaniline

The temperature variation of density and ultrasonic velocity of the liquid crystal hexyloxybenzylidene phenylazoaniline are reported. The density across the smectic A-smectic B transition is more predominant than the other transitions. The density variation with temperature and the calculated thermal expansion coefficients suggest that the transitions isotropic liquid-nematic, nematic-smectic A and smectic A-smectic B are of first order. Anomalous behaviour of ultrasonic velocity is observed across the isotropic liquid-nematic transition and prominent dips in velocity are observed at the nematic-smectic A and smectic A-smectic B transitions. The adiabatic compressibility (βad) Rao number (Ra) and molar compressibility (B) are estimated using the experimental density and ultrasonic velocity

Phase transition studies of the liquid crystal pentyloxybenzylidene phenylazoaniline

Phase transition studies of the liquid crystal pentyloxybenzylidene phenylazoaniline are investigated with density and ultrasonic velocity measurements. The density variation with temperature confirms that the isotropic liquid-nematic, nematic-smectic A and smectic A-smectic B transitions are of first order. The temperature variation of ultrasonic velocity confirms all the phase transitions. The adiabatic compressibility (βad), Rao number (Rn) and Molar compressibility (B) are estimated from density and ultrasonic velocity

Phase transition studies of the liquid crystal 4-[4-n-hexyloxybenzylidene amino] azobenzene thermal microscopy and DSC

The phase transition temperatures of the liquid crystal 4-[4-n-hexyloxybenzylideneamino]-azobenzene have been investigated by the thermal microscopy and the Differential Scanning Calorimetric (DSC) studies. These studies confirm that this mesogen exhibits nematic, smectic A and smectic B phases. The transition enthalpies, transition entropies and also the textures exhibited by the different phases are presented