Phase transitions, optical, dielectric and viscoelastic properties of colloidal suspensions of BaTiO₃nanoparticles and cyanobiphenyl liquid crystals

Abstract

We report experimental studies on the phase transitions and physical properties of colloidal suspensions of BaTiO3 nanoparticles and two cyanobiphenyl liquid crystals (4-pentyl-4ʹ-cyanobiphenyl and 4-octyl-4ʹ-cyanobiphenyl). From the differential scanning calorimetric measurements, we show that the nanoparticles have antagonistic effect on the isotropic to nematic and nematic to smectic-A phase transitions. The birefringence, dielectric anisotropy and splay elastic constant remain almost unchanged, whereas the bend elastic constant and rotational viscosity decrease considerably. The experimental results are discussed based on the possible contribution of BaTiO₃ nanoparticles and free surfactant molecules in the suspensions.