U.S.-Germany Cooperative Research in Secondary Ion Mass Spectrometry

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This award supports Professor David M. Hercules of the University of Pittsburgh and two of his graduate students to collaborate in analytical chemistry research with Professor Alfred Benninghoven and his group of the University of Muenster, Germany. Together they will study fragmentation of polymers subjected to ion and neutral bombardment, and gas phase decomposition of polymers. They will also develop methods for determining molecular weight distributions of polymers sampled directly from solids. This research, supported jointly by the U.S.-Germany Cooperative Science Program of the Division of International Programs and the Analytical and Surface Chemistry Program in the Chemistry Division, will continue the collaboration between the PI, a surface scientist known for his development of electron spectroscopy for chemical analysis and for his work on secondary ionization mass spectrometry (SIMS), and a world class German chemist who originated a particular design of time-of-flight SIMS instrument, which provides high sensitivity and moderate resolution for spectra from complex samples. Dr. Hercules has obtained the second of these instruments, so collaboration will allow the US partners to quickly reach the state of the art in this complex technology. The German col- laborators will obtain added expertise in SIMS sampling of polymers. Polymers are long chain molecules, whose use has resulted in humanity's ability to design structural materials and lubricants to suit a variety of needs, without being restricted by nature's more limited repertoire. Polymers are generally "polydisperse" i.e. the result of making a polymer is a group of related molecules of similar structure but different length. Understanding such length differences requires sampling the solid polymer without changing the chain-length distribution or dispersity, a difficult task. Polymer scientists in general require better methods for studying polymer structure in solids. Linking the sampling methods (developed by Dr. Hercules) together with the structural measurement techniques (developed by Dr. Benninghoven) will be a significant contribution to fundamental and applied research in analytical chemistry.