Effect of SiO2 nano Particle Dispersion on the Structural and Dielectric Behaviour of Iyotropic Liquid Crystalline Phase

Abstract

Present study is an effort to understand the effect of SiO2 nano- particles (5-15 nm) on the variety of lyotropic liquid crystalline (LLC) phases obtain from cationic and anionic [ Cetyl perydinium chloride (C21H38NCl), N-Cetyl-NNN, Trimethyl ammonium bromide (C19H42BrN) and Sodium dodecyl Sulphate [(C12H25SO4Na)] amphiphilic molecules in the non-aqueous medium of the protic polar solvent ethylene glycol (EG). The prepared pure and dispersed LLC phases were characterized by using polarizing optical microscope (POM), X-ray diffractometer (XRD), LCR meter and Fourier transform infra-red spectroscopy (FTIR) to examine the optical, structural, dielectric and chemical behvaiour. Morphological and structural characterizations reveal that addition of Si particles does not affect the ordering and structure of the LLC phases in any case. Lamellar to hexagonal phase transition has been noticed in the CTAB based sample dispersed with 0.5wt% Si. It was found that dielectric permittivity found to be decreased with addition of Si particles in LLC phases derived from cationic surfactants, however, addition of Si particles in SDS based samples enhance the permittivity. No chemical interaction has been noticed in the Si dispersed samples.