The Dielectric Behavior of Straight Chain Alcohol Blends

Time Domain Spectroscopy (TDS) has been used in this study to determine the dielectric relaxations of several mixtures of normal alcohols. The complex permittivity ε* (ω) was determined in the frequency range from 106 to 5×109 Hz for temperatures ranging from -20 to 500C. Mixtures of n-octanol and n-butanolin mole concentrations of 95, 75, 50 and 25% were studied. From plots of the primary relaxation time, Tl, against temperature, activation energies ΔH of 0.45± 0.02 eV were found for all mixtures investigated, and values of static dielectric permittivity were seen to follow a linear mixing law. Two relaxations were observed with both mixtures and neat alcohols. The primary relaxation time Tl, which characterizes the low frequency dispersions, ns, changed substantially with varying proportions, while the secondary relaxation time Ti did not. Resolution ution of the data for T2 was, however, poorer than those for Tl. There was no indication of change in the relaxing species with temperature below 40°C, while some evidence of dissociation was found at temperatures above 40°C.