Charles Deering McCormick Professor of Teaching Excellence

We seek to understand the dynamics of complex fluids during flow. Many fluids encountered in chemical and materials processing exhibit non-Newtonian behavior, due to the presence of molecular or nanoscale structure that is perturbed by flow. Our research emphasizes in situ investigation of such flow-induced structural changes to elucidate the origins and mechanisms of complex rheology in polymers. These efforts also inform polymer processing technology, since microstructural changes induced by flow can have a strong influence on final product properties.

Our research is broadly divided between two thrusts. We have long-standing interest in how flow affects the macroscopic organization of structured fluids, such as surfactants, ordered block copolymers and liquid crystalline polymers. We are developing powerful x-ray scattering techniques for real-time measurements of polymer structure in both idealized shear flows and during processing, taking advantage of Northwestern's synchrotron research facility at the Advanced Photon Source. Our other theme is the application of unique flow birefringence techniques to interrogate stresses generated in polymer melts and solutions and to test nonlinear constitutive models for the rheological behavior of flexible polymers.