Magnetorheological and Electrorheological Suspensions. The magnetorheological (MR) and electrorheological (ER) responses are the dramatic variation in suspension rheological properties due to large applied magnetic and electric fields. Development of proposed applications, including MR and ER clutches, brakes, engine mounts and robotic actuators, is currently limited by a lack of understanding of the underlying mechanisms and by the inability to produce effective, durable suspensions. Our research addresses each of these issues.
Fiber Suspension Rheology. The behavior of fiber suspensions is important to many industrial processes, from papermaking to processing reinforced composites. Our approach focuses on understanding the relationships between fiber properties and interactions, suspension structure and rheological properties of non-Brownian fiber suspensions. We combine experiments probing the microstructure and rheology, "molecular" simulation techniques, and theoretical development to probe the above relationships. Particular problems that we address include the role of fiber flexibility and concentration on the entanglement and flocculation of fibers, the rheological response of entangled networks, and the evolution of anisotropy in these suspensions. Our research concentrates on understanding the fundamental chemistry and physics of transport processes of heterogeneous media, particularly the role of colloidal and interfacial properties on the mechanical and rheological properties of materials. Applications of this area of research are quite broad, ranging from synthesizing new materials to to processing of lignocellulosic biomass to understanding diseases in the human body. Many new and interesting systems suffer from a lack of fundamental understanding and experimental data, inhibiting development and applications. Our research program contains both an experimental effort and the analytical work required to fully understand the controlling factors. Our ultimate goal is to understand the underlying chemistry and physics in order to improve processes and material properties.