Application of Classical Thermodynamics to Conductivity in Nonpolar Media: Experimental Confirmation

Abstract

We previously proposed ( Gourdin-Bertin , S. and Chassagne , C. J. Chem. Phys. 2016 , 144 ( 24) ) a simple theoretical model to account for the evolution of conductivity with dielectric permittivity in nonpolar media. In this article, we validate the theory experimentally for the case of an ionogenic species kept at a constant chemical potential (i.e., in equilibrium with a nondissolved salt, in contrast to previously published conductivity measurements carried out as a function of various fully dissolved salt concentrations). To our knowledge, it is the first time that this type of experiment has been performed explicitly.

Electrical Conductivity and Viscosity in Binary Organic Liquid Mixtures: Participation of Molecular Interactions and Nanodomains

“…In a subsequent investigation of toluene mixtures with several different alcohols, Dukhin and Parlia [33] suggested that electrical conductivity depends on the concentration of ion pairs, which varies with the dielectric constant of the mixtures. However, others have subsequently questioned these explanations, on the grounds that they do not adhere to classical thermodynamics [34,35]. In addition, Gourdin-Bertin and Chassagne [34] reasoned that autoprotolysis would not account for the observed electrical conductivity behavior because only very low concentrations of ionic species would be present.…”

“…Moreover, the role of composition-dependent ion pairing was also questioned [34]. However, on the whole, even though the previous studies have presented accompanying theories that apparently give acceptable fits to the experimental data, the overall picture is confusing, with impurities also being implicated, including water [34][35][36], with the overall conclusion being that further work was required [34].…”

“…The inset in Figure 6 shows the linearity of the low concentration dodecane/octanol data (i.e., ≤15 wt%) plotted on linear axes. In addition, by way of comparison, data from Gourdin-Bertin and Chassagne [35] for n-heptane/1-dodecanol mixtures in the presence and absence of an excess of solid potassium chloride are also indicated in this figure. It is clear that, notwithstanding the uncertainties associated with differences in the conditions under which the low conductivities of liquid hydrocarbons were measured (we estimate uncertainties in our data to be within ±5% of the indicated values), there is general consistency between the different sets of data.…”

“…The solid line is for poly(α-olefin) (PAO)/1-octanol mixtures from Bombard and Dukhin [32], which were measured at 1 Hz. The open and filled squares are from Gourdin-Bertin and Chassagne [35] for the n-heptane/1-dodecanol system in the presence and absence of excess solid potassium chloride, respectively. The inset shows low concentration data for the dodecane/octanol system on linear axes.…”

Structure and conductivity of AOT solutions in n‐hexadecane‐chloroform mixtures

“…More rarely the conductivity of surfactant solutions is enhanced using mixtures of polar and nonpolar solvents. For example, it was shown in [32] that conductivity of AOT solutions in the ethanol–toluene mixtures increases from 5 × 10 −11 to 10 −4 S/m with raising the ethanol content in the mixture. It is known also that the addition of chloroform to nonpolar solvents increases conductivity of the solutions [33, 34].…”