(68c) Influence of An Applied Electric Field On Phase Behavior and Microheterogeneity

Previous experimental studies [1] indicate that o-nitrotoluene/n-decane and m-nitrotoluene/n-decane mixtures are of particular interest as they exhibit anomalous behavior in the non-linear dielectric effect near the upper critical solution point, and it has been surmised that these effects are due to an increase in cluster formation as each mixture approaches its critical point. In this work, Monte Carlo simulations are performed using the TraPPE force field at multiple temperatures, concentrations, and electric field strengths in order to examine the structural microheterogeneity of these mixtures and determine the dielectric constants and non-linear dielectric effect. At low field strength, the simulations indicate substantial structural microheterogeneities but these persist over a wide range of conditions. At high field strength (an order of magnitude higher than in the experimental work), the simulations indicate a field induced segregation.

In addition, Gibbs ensemble Monte Carlo simulations are used to explore the influence of applied external field on the vapor-liquid phase equilibria of neat water, methanol, and dimethyl ether.

[1] M. Sliwinska-Bartkowiak, B. Szurkowski, and T. Hilczer, Chem. Phys. Lett. 94, 609 (1983).