The Nanoscale and Quantum Phenomena Institute (NQPI) Seminar Series is pleased to welcome Sumit Sharma, Associate Professor, Department of Chemical and Biomolecular Engineering, Ohio University, as our featured speaker on Thursday, September 3 at 4:10 p.m. All seminars take place in Walter 145 and are also accessible virtually via Teams.

Title: Formation and Stability of Self-Assembled Monolayers of Surfactants at Metal-Water Interfaces Studied Using Molecular Simulations

Abstract: Adsorption of surfactants is a facile way of adjusting the interfacial properties of metals with numerous applications. The traditional viewpoint is that the adsorption of surfactant molecules on metals is driven by a strong affinity of the polar head groups for metals, and that surfactant molecules adsorb in a planar self-assembled monolayer (SAM). Using molecular simulations and statistical mechanics theory, we show that the traditional view is imprecise on many fronts. Hydrophobic interactions between alkyl tails of surfactants play an active role in the adsorption. Surfactants adsorb in various morphologies (planar SAM, cylinders and spheres) depending on their molecular geometry. The adsorbed morphologies may undergo transitions when the hydrophobic interactions are perturbed by exposing the adsorbed surfactant films to oil molecules. Surfactant micelles experience a free energy barrier to adsorption, while free surfactant molecules do not experience any such barrier.

Bio: Dr. Sumit Sharma is an Associate Professor in the Department of Chemical and Biomolecular Engineering at Ohio University. His research combines molecular modeling and simulations, thermodynamics, and statistical mechanics to investigate the behavior of surfactants and proteins near interfaces. Dr. Sharma is a recipient of the National Science Foundation CAREER Award and the American Chemical Society Petroleum Research Fund Award. He earned his Ph.D. in Chemical Engineering from Columbia University and was a postdoctoral researcher at Princeton University.