Functionalized Nanostructures at Interfaces

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In this project, funded by the Macromolecular, Supramolecular and Nanochemistry Program of the Chemistry Division, Prof. Janice E. Reutt-Robey of the University of Maryland, College Park, and her students will use a combination of scanning probe microscopy and spectroscopy measurements to image functionalized carbon-based C70 nanoparticles and nanoassemblies at crystalline surfaces. This research will determine how functional groups influence the transport, stability and structural arrangements of nanoparticles at interfaces. Prof. Reutt-Robey and her students will undertake systematic measurements of two nanomaterial classes: (1) covalently functionalized nanoparticles and (2) nanomolecular assemblies joined by weak (noncovalent) forces. They will develop vacuum-compatible liquid delivery methods, based upon microaerosols and microliquid jets, for the controlled deposition of nanomaterials at well-defined surfaces. They will obtain detailed topographic and potentiometric contours of discrete species by UHV Scanning Probe Microscopy through complementary tunneling-based and force-based measurements. The impact of nanoparticle electric moment, polarizability, and stereo features on structure and dynamic evolution will be determined for pristine nanoparticles and for solvated nanoparticles and nanoassemblies. Molecular-level mechanisms for nanoparticle motion, disassembly and nanocrystallizaiton under different thermochemical stimuli will be measured. This project will provide laboratory research experiences for graduate and undergraduate students and junior scientists with direct exposure to cutting-edge experimental methods and instrumentation. Students and researchers will gain expertise in nanoparticle characterization, thin film growth and the preparation of advanced materials. Additionally, students will become trained in quantitative scanned probe measurements and analysis and will receive hands-on training and experience in surface-sensitive microscopies and spectroscopies and vacuum science. The project consists of a systematic exploration of nanoparticle structure and dynamics at chemical interfaces, which will provide detailed information on how nanoparticles diffuse at surfaces and arrange into functional structures. The external field tunability of nanoparticle orientation during growth and trapped in multilayer films will be quantified through structural and impedance spectroscopic measurements. Students and researchers will have significant opportunities to participate in educational and outreach activities with broad national, international and societal impact.