Guy C. Berry

Guy C. Berry

Carnegie Mellon University

1935 – Present

Chemical Engineer
Awarded Bingham Medal 1990
Emeritus Fellow, Elected 2015

Guy Curtis Berry was born in Greene County, Illinois on May 11, 1935. He attended the University of Michigan for both his undergraduate and graduate degrees, obtaining a B.S. in Chemical Engineering in 1957, an M.S. in Polymer Science in 1958, and a Ph.D. in Chemical Engineering in 1960. He worked as a Fellow at the Mellon Institute after graduation and was promoted to Senior Fellow in 1965. He moved into an Associate Professor position at Carnegie Mellon University in 1967 before becoming a Professor of Polymer Science and Chemistry in 1973. He was made University Professor of Polymer Science & Chemistry in 2002, before moving to Emeritus status in 2004. He also held a number of leadership responsibilities at the University serving as Acting Dean of the Mellon College of Science in 1981-82, Acting Head of the Department of Chemistry in 1983-84, before becoming Head of the Department of Chemistry from 1990-1995.

Solutions and melts of flexible polymers have interested Berry throughout his career. In 1968 he and T. G. Fox published what is still the definitive work on the factors that govern the viscosity of polymer melts and concentrated solutions. Though nominally a review, this contribution contained much original work, including the proposal that the viscosity of branched polymers is an exponential function of branch length as well as a wide-ranging and critical examination of diluent effects. Both ideas have motivated considerable theoretical and experimental study that continues to the present day. About the same time, Berry began an extensive investigation of thermodynamics and flow behavior in dilute polymer solutions. His beautiful studies of linear and star-branched polymers have remained for many years the “primary standard” for judging dilute solution theories. Berry turned his attention to more concentrated solutions in order to clarify the influence of chain dimensions on viscosity and to explore the molecular-weight and concentration dependence of a broad range of rheological properties. Through shear creep and recovery experiments, he demonstrated the utility of a “critical strain” criterion for the onset of nonlinear response. He combined those results with a simplified form of the BKZ constitutive equation to provide a general framework for systematizing the rheological behavior of flexible polymer solutions.

Berry's latter work dealt with heterocyclic condensation polymers, some of which are regular enough and rigid enough to approximate molecular rods. They can form ordered (nematic) solutions and are typically subject to strong intermolecular forces of electrostatic origin. Berry and his group created a unique and systematic body of results on the rheology of rod-like polymer solutions. An especially valuable contribution was the contrast and comparison of flexible-chain and rod-like polymer rheology. He demonstrated that isotropic solutions of rod-like polymers obey the same laws (with appropriately redefined coefficients) as flexible polymers. He also carefully documented the qualitative differences in linear response that develop above the ordering transition, as well as showing that the corresponding nonlinear behavior at large strains and elevated shear rates settles back toward the isotropic flexible polymer solution results.

Berry is a member of the American Chemical Society, The Society of Rheology, the Japan Society of Rheology, the American Chemical Society, the American Physical Society, the Materials Research Society, and the American Association for the Advancement of Science. He has been honored in numerous ways, included appointment as a Fellow of the American Physical Society, American Chemical Society, and The Society of Rheology. Besides the Bingham Medal, he won the Pittsburgh Prize (1994) and the Distinguished Service Award, Pittsburgh Section, from the American Chemical Society. He has held positions as Visiting Professor to Kyoto University, Colorado State University, and the University of Tokyo, and he has served in an editorial capacity for the Journal of Polymer Science, the Journal of Rheology, and Progress in Polymer Science.

Berry is known as a superb experimentalist with sound theoretical instincts, working with structurally well-defined materials, choosing experiments with an eye toward clean interpretation, and using theory, when available and appropriate, with imagination and good judgement. Berry was awarded the Bingham Medal to honor his more recent contributions to the field of rheology as well as his career-long endeavor to bring a deeper understanding to the molecular origins of rheological properties.


Guy C. Berry. Faculty & Research, Chemistry, Carnegie Mellon University (accessed August 16, 2019).

Guy C. Berry. Department of Chemistry, Carnegie Mellon Univeristy (accessed August 16, 2019).

Berry, Guy Curtis. American Men and Women of Science, 29th ed.; Gale: Farmington Hills, MI, 2011; Vol. 1.

Berry G.C., Fox T. The viscosity of polymers and their concentrated solutions. In Fortschritte der Hochpolymeren-Forschung. Advances in Polymer Science, vol 5.; Springer, Berlin, Heidelberg, 1968; pp. 261-357.

Note: This biography is an adaptation of the following articles previously published by The Society of Rheology.

Guy C. Berry, 1990 Bingham Medalist. Rheology Bulletin 1990, 59(2).

Photo Credit

AIP Emilio Segrè Visual Archives.