The state-of-the-art membranes for desalination are comprised of thin film composites where the permselective layer is a thin but highly crosslinked, interfacially polymerized polyamide. Although effective, the rapid polymerization rate and reaction conditions produce films with rough surface structures and chemical heterogeneity, which precludes some advanced characterization techniques. In 2011, we proposed a paradigm shift in how these types of membranes are fabricated, where the selective layer is created layer-by-layer through a reactive deposition process. By doing so, we can create membranes that are smooth, tailorable, and exceptionally thin (10’s nm). In this presentation, I will highlight the development of our automated deposition system for making tailored model polyamide membranes and present recent measurements of performance of these membranes through dead-end filtration. I will also present some recent advanced measurements of network structure and dynamics on these types of membranes that challenge our understanding of the operative transport mechanism in these materials.
Christopher M. Stafford is a research staff scientist and project leader in the Materials Science and Engineering Division at the National Institute of Standards and Technology. In 2010, he initiated a research program focused on measuring the structure, dynamics and transport of polymer membranes, with applications in water purification, fuel cells and batteries. Previously, he has conducted research in surface/wrinkling instabilities, polymer adhesion, and combinatorial and high throughput methods. Prior to joining NIST, Dr. Stafford received his Ph.D. from the University of Massachusetts, Amherst and his B.S. from the University of Southern Mississippi. Since joining NIST, Dr. Stafford has received numerous awards and honors, including the U.S. Department of Commerce Silver Medal in 2005 and the NIST Bronze Medal in 2007. He was also recognized with the NIST Sigma Xi Young Scientist Award in 2006 and the Adhesion Society Outstanding Young Adhesion Scientist Award in 2010. He was elected as an APS Fellow in 2017 and an ACS PMSE Division Fellow in 2018.
Seminar sponsored by the Department of Chemical and Biomolecular Engineering