ChE 2025 Fall Seminar Series

Details

Speaker: C. Heath Turner, Ph.D
Department of Chemical and Biological Engineering
The University of Alabama, Tuscaloosa, AL

Abstract: The formation and structural/chemical evolution of nanostructured materials involves processes that span a wide range of time and length scales. This includes bond-breaking and bond-formation steps, as well as concerted structural relaxations within the materials. These events have characteristic time scales ranging from femtoseconds up to minutes/hours, so preserving atomistic details in a single computational model is particularly problematic. In this presentation, I will describe kinetic Monte Carlo (KMC) approaches that we have developed for capturing the relevant kinetics and equilibrium thermodynamics in amorphous materials, along with applications to several different materials platforms. Due to the underlying event-based nature of the KMC simulation technique, time scales can be extended by several orders-of-magnitude, well beyond traditional atomistic simulation approaches. Furthermore, we have developed an automated process for cycling between KMC and MD stages; the KMC events are able to capture the reaction events (potentially involving long time scales), while the MD simulations are able to capture events involving concerted motions during structural relaxation. The relative computational efficiency of our hybrid KMC-MD method allows for large parameter spaces to be rapidly explored, as well as automated feedback comparisons against experimental benchmark data. Several different applications will be highlighted: (a) growth of Au nanoparticles in solution; (b) gas separation performance of ionic polyimide membranes; (c) growth of amorphous tribofilms on metal surfaces; and (d) dehydrochlorination of PVC plastic.

Bio: Prof. Turner completed his B.S. in Chemical Engineering from Auburn University and his Ph.D. in Chemical Engineering from NC State University. He spent several years in industry with Monsanto, Birmingham Steel, and Trinity Consultants. He initially joined the University of Alabama as an Assistant Professor in 2003. He served as the Head of the Department of Chemical and Biological Engineering for the past 7 years, during which time the department moved up 45 positions in the U.S. News and World Report Rankings, the graduate program grew by 300%, and research expenditures grew by 500%. He is the inaugural Director of the UA Polymers and Soft Materials (Poly-SM) Research Center, and he currently serves as the Associate Dean for Research and Economic Development in the College of Engineering. Over the past several years, he has been a visiting Faculty Fellow at NASA-Langley, the Naval Research Lab, and the Air Force Research Lab, Visiting Professor at Vanderbilt University, and an International Distinguished Professor at Shanghai University of Engineering Science. He has published approximately 140 journal articles in the areas of computational catalysis, interfacial phenomena, ionic liquids, and polymers, with the goal of making stronger connections to experimental observables.

Talk Title: Modeling Amorphous Materials with Integrated Kinetic Monte Carlo and Molecular Dynamics Simulations