Sergio E. Quiñones-Cisneros, Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Apdo. Postal 70-360 Cto. Exterior, Ciudad Universitaria., Mexico D.F., 04510, Mexico and Ulrich K. Deiters, Institute of Physical Chemistry, University of Cologne, Luxemburger Str. 116, Cologne, 50939, Germany.
The contributions of John O'Connell to the broad understanding of thermodynamic properties of complex fluids can find an important influence in many modern areas of research regarding thermophysical and transport properties. Just as a clear example, advancements in areas such as the development of modern equations of state (EoS) based on statistical mechanics and group contribution methods have an unquestionable precedent in the core contribution John O'Connell made in the area. It is, therefore, hard to imagine a modern thermodynamic development that, to one degree or another, has not been influenced by the related ideas that have been intensively developed over the last 50 years – a field on which John O'Connell has been one of the major players. In this context, our work with the friction theory (FT) closely links and extends the physics already considered in the development of an EoS with modeling and even prediction of viscosity (J. Phys. Chem. B, 110, (25), 12820, 2006). The friction theory, which has already achieved a good deal of success for many diverse and challenging cases, is fundamentally based on the EoS that is at the core of the FT viscosity models. A main result of the approach is the revealing of a close connection between the FT derived models and the physics that is already present in the EoS upon which the FT viscosity models are based. This close connection has allowed for the prediction of very interesting phenomena such as the low-temperature viscosity anomaly in water or, even more interesting, the critical divergence of the viscosity – a phenomenon so weak that it can only be seen at microgravity conditions. This may also bring together two areas of high interest: non-equilibrium and equilibrium thermodynamics – at least as limiting cases. This presentation will then focus not on particular viscosity models, but rather in demonstrating how the physics of some thermodynamic models can be mapped upon the viscosity surface – bringing into the area of transport properties an immeasurable richness in experience and knowledge achieved throughout the intense development that EoS have had over the last half century.