On the morning of May 14, Professor Ronald G.Larson, a member of the U.S. National Academy of Engineering and a professor atthe University of Michigan, was invited to visit the School of Emerging SoftMatter. He delivered an academic lecture titled Multi-ScaleSimulations of Rheology and Flow of Commercially Important Materials: Paints,Shampoos, and Polyethylenes.

The structural and flowproperties of viscous or elastic fluids are sometimes referred to ascomplex fluids. Through multiscale simulations—including moleculardynamics (MD), Brownian dynamics (BD), and continuum fluid mechanics modeling—itis possible to compute the continuum-level thermodynamic, rheological, and flowproperties of complex fluid materials relevant to industrial and consumerapplications.

During the lecture,Professor Larson's presentation primarily focused on two key aspects: (1) Coarse-grainedmodeling of wormlike surfactant solutions and polymer-colloid mixtures. Byemploying coarse-grained methods, he simulated the formation and dynamictransition mechanisms of bridging and loop structures. This approach allowedthe calculation of multiple relaxation times in the dynamics and rheology ofpolymer-like systems used in consumer and industrial products, suchas shampoos and paints. (2) Simulation of the film-blowing process forpolyethylene polymers. This part explored the versatility and complexity ofpolyethylene, particularly the effects of branching on its performance, to gaindeeper insights into its processing behavior.

Professor Larson's work demonstrates thefeasibility of multiscale simulation methods in studying the structure ofcomplex fluids. By comparing simulation predictions with experimental data, hisresearch extracts valuable information that is otherwise difficult orimpossible to obtain through experiments alone.

Professor Larson is currently in the Department of ChemicalEngineering at the University of Michigan. His primary research focuses on therheology of complex fluids—such as polymers, colloids, surfactants, and liquidcrystals—as well as the commercialization of related material products. In2003, he was elected as a member of the U.S. National Academy of Engineering.