Phase Transition Studies in Polymesomorphic Compounds II. Ultrasonic Velocity Studies in N(p-n-Heptyloxy Benzylidene)p-n-Butyl Aniline

Abstract

The variation of ultrasonic velocity in N (p-n-heptyloxy benzylidene)p-n-butyl aniline, (HyBBA) with temperature in isotropic, nematic, smectic-A, smectic-C and smectic-G phases is measured. All the phase transitions I-N, N-SA, SA-SC and SC-SG are found to be of first order. The adiabatic compressibility βad, molar sound velocity or Rao number Rn, and molar compressibility or Wada constant AW are computed. Rn and AW of HyBBA are compared with theoretical values and found to be in good agreement with the theory.