Structural Investigation of a Water/n‐Heptane Interface: A Molecular Dynamics Study

Abstract

Molecular dynamic simulation techniques have been used to study the equilibrium configuration of a water/n‐heptane interface. The simulations were carried out using a readily available commercial software package, with Ewald sums to estimate the long‐range interactions. The effect of the interface on the molecular structure of n‐heptane was investigated and the interfacial width estimated from interfacial density profiles. Interfacial tension was evaluated using both the well‐established pressure tensor method as well as the more novel capillary wave theory. The results provide the basis for further study of aqueous/organic interfaces relevant to solvent extraction processes.

Keywords:

• Molecular simulations
• molecular dynamics
• heptane
• interface
• interfacial tension

Acknowledgments

We would like to thank Dipl.–Ing. Daniel Demicoli and Professor Johann Stichlmair from the Institute of Thermal Process Engineering at The Technical University of Munich for their direction, assistance, and suggestions during Mr Riedleder's time in Australia. Support from the Particulate Fluids Processing Centre, a Special Research Centre of the Australian Research Council is gratefully acknowledged. Financial support from the University of Melbourne through a Melbourne Research Grant Scheme Early Career Researcher award is also acknowledged.