Dept. of Chemistry Seminar – Dr. Chrys Wesdemiotis
About the event
Speaker: Dr. Chrys Wesdemiotis, The University of Akron
Host: Dr. Ivan Popov
Title: Mass Spectrometry Advances for the Characterization and Imaging of Polymeric Materials
Abstract: Progress in science and engineering relies increasingly on synthetic materials with well-defined structures, optimized to perform specific biomedical, technological, consumer, and environmental applications. Mass Spectrometry (MS) using matrix-assisted laser desorption/ionization (MALDI) and/or electrospray ionization (ESI) provides a powerful and versatile tool for the molecular characterization of such compounds as well as for imaging the molecular composition and defects of solid polymer surfaces. The dispersive nature of MS permits the conclusive and confident elucidation of molecular weight, functionality, and end group distributions and are particularly suitable for monitoring reactions that change the mass. Complex multicomponent blends can be simplified with multidimensional approaches, involving in-line separation by polarity, using liquid chromatography (LC), and/or by ion size and shape, using ion mobility (IM) spectrometry. Meanwhile, large macromolecules and crosslinked networks can be made analyzable by mild thermal degradation that predictably breaks weak bonds while preserving connectivity and functionality. Conversely, mass spectrometry imaging (MSI) techniques with solvent-free MALDI can be utilized to determine the molecular composition and defects in the top molecular layer of synthetic polymer surfaces (<2 nm), which can differ from the composition of the bulk due to segregation or environmental factors. In all cases, additional insight on primary structure, sequence, architecture, and topology can be gained through tandem mass spectrometry (MS/MS) fragmentation. Our group utilizes such multidimensional approaches to elucidate the microstructures of a broad range of polymeric materials, including variously shaped (co)polymers, complex conjugate blends, crosslinked materials, labile/reactive oligomers, and solid surfaces.
Bio: Chrys Wesdemiotis completed his Ph.D. at Technische Universität Berlin (1979). After a postdoctoral fellowship with Fred W. McLafferty at Cornell University (1980) and military service in Greece (1981–1983), he returned to Cornell as senior research associate (1983–1989). In 1989, he joined the University of Akron, where he currently is Distinguished Professor of Chemistry, Polymer Science, and Integrated Bioscience. Research in the Wesdemiotis group focuses on the development and application of mass spectrometry methods for the characterization and imaging of synthetic polymers, advanced materials, and polymer–biomolecule conjugates. The Wesdemiotis group has published >400 peer-reviewed papers. Prof. Wesdemiotis has mentored 24 M.S. and 42 Ph.D. graduates so far. He has served in many Review Panels and Journal Editorial Boards. His awards include an NSF Special Creativity Award and the American Chemical Society – Rubber Division George Stafford Whitby Award for Distinguished Teaching and Research.