Donald E. Sullivan

Dr. Donald E. Sullivan
Professor Emeritus


I obtained my B.Sc. degree at McGill University in 1972, majoring in chemistry. I then went on to graduate studies at the Massachusetts Institute of Technology, Department of Chemistry, specializing in statistical mechanics of liquids, and graduated with a Ph.D. in 1976. Following that, I did a 16-month postdoc at the State University of New York at Stony Brook, Department of Mechanics, again researching several aspects of the statistical mechanics of liquids, especially interfacial phenomena. I then did a further 8-month postdoc at the National Research Council in Ottawa, continuing my previous research.

Professional Experience

In September 1978, I joined the faculty of the Department of Physics at the University of Guelph, where I have been ever since. Since then, I have held short-term Visiting Professorships at Cornell University and McGill University. From 2002 to 2005, I served as Director of the Guelph-Waterloo Physics Institute, the joint graduate program in physics at the Universities of Guelph and Waterloo. Prior to that, as well as in the period following that until 2008, I also served as departmental graduate coordinator.

My work has focused on the nature of the interactions between molecules of these systems which can produce such LC phases, most recently in polymers. In particular, I have concentrated on the effects of so-called “excluded-volume” interactions, which basically result because the presence of a molecule excludes any other molecules from occupying the same space and are always present regardless of any other types of interactions. The statistical description of these systems is complicated due to the fact that polymeric molecules are flexible or “wiggly”, i.e., cannot be simply pictured as straight pencils, which leads to several mathematical complexities. Recently, I have studied two models, both in the framework of what is called “self-consistent field theory”. One is a discrete model, in which a polymeric molecule is constructed from a chain of hard-sphere beads. The other model is a continuum version of the first one, what’s called the “wormlike-chain” model, in which the polymers are pictured as flexible strings. The approaches to solving the theory for these models rely heavily on numerically-intensive computational techniques, facilitated in large part by SHARCNET. The two models yield complementary information on aspects such as dependence of phase boundaries, i.e., the relation between density and pressure, on properties such as the length-to-width ratio of the molecules and their degree of flexibility. Besides polymers, one other type of system to which these studies have been successfully applied is aqueous suspensions of certain viruses.