Dielectric spectroscopy of organic solvents of varying polarity

Aljabal, Zena (2016) Dielectric spectroscopy of organic solvents of varying polarity. Masters thesis, Memorial University of Newfoundland.

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Abstract

The dielectric constant and the conductivity for several organic solvents of varying polarity and for colloidal suspensions are measured using dielectric spectroscopy as a function of frequency, over the frequency range 0.1 Hz to 100 kHz. These measurements are carried out for organic solvents of different polarities: cyclohexyl bromide (CHB), castor oil, cis+trans-decahydronaphtalene (decalin) and decane. In addition, dielectric spectroscopy is carried out for polymethylmethacrylate (PMMA) colloidal spheres in the intermediate polar mixture of cyclohexy bromide (C₆ H₁₁ Br,(CHB)) and 20% cis+trans-decalin by volume. The primary result in this thesis is the examination of electrode polarization effects, which were observed at low frequency in CHB and CHB-decalin mixtures. A simple model function for sample impedance coupled with electrode polarization, involving a power law dependance of the polarization capacitance on frequency, provided an excellent fit to the dielectric spectra at low and high frequencies. These measurements provide direction for future measurement on colloidal suspensions in these solvents.

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