Gradient theory of surface tension of pure fluids: Effect of molecular shape and polarity

In this paper, we investigate the effect of molecular shape and multipolarity on interfacial properties using a modified van der Waals theory of interfaces and an equation of state developed by Mohanty and Davis for attracting, nonspherical particles with a rigid, convex core. The equation of state contains, in addition to the classical van der Waals parameters, molecular shape and multipolar parameters. Our results indicate that the dimensionless surface tension of pure fluids varies linearly with the multipolar parameter and exponentially with the molecular shape parameter. The agreement between our predictions and experimental data is good. © 1991