MRI: Acquisition of an AFM System for Imaging and Characterization of Synthetic Nanostructures and Native Biological Macromolecules

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0922400ParkWilliams College"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)."Technical Summary: AFM?s ability to image and characterize surface topography, identify nanoscale regions of samples via phase or force imaging, and even alter surfaces, has made it an indispensable tool in research on systems with nano- and micro-scale features. Several research programs at Williams (in chemistry, physics, biology, computer science) require these capabilities. The Park group focuses on the design of polymeric materials which will self- organize (based on hydrocarbon-fluorocarbon interactions within the polymer chain, as well as interactions with chemically patterned surfaces) to give films with internal architectures for enhanced performance in organic photovoltaic devices; AFM will be used to characterize the polymer films, the surfaces on which they will be cast, and to pattern substrates via DPN. Using the imaging capabilities of AFM at elevated temperatures, Lopes? group studies the evolution of defect structure in diblock copolymer films. From ?movies? gathered in situ, the group studies the defect dynamics and kinetics as a function of temperature to better understand the self-assembly processes in such materials. The Ting group studies photosynthesis and related processes in marine microorganisms that have a major role in global carbon cycles. AFM will be used to characterize the architecture of the photosynthetic apparatus in native membranes and to study how alterations in the organization and stoichiometry of these protein complexes within a bilayer will affect photosynthesis. AFM will also be used by several other researchers at Williams, including the Goh group, which studies the design of biopolymer-based targeted drug delivery vehicles with improved biocompatibility and tenability of drug release. Goh will use imaging to characterize the location of differing materials within triblock copolymer structures and force curve measurements to aid in structure determination. The Banta group is exploring the function of virulence proteins in the soil bacterium A. tumefaciens; AFM will be used to study the mode of binding of these Vir proteins to DNA and, thus, the role these proteins play in promoting T-DNA delivery to host plant cells. McGuire?s work will use topographical information from AFM of surfaces to improve models for describing light scattering off of surfaces in computer graphics and to search for models of scattering from surfaces which will improve ray tracing and reduce their computational load. The AFM at Williams will be incorporated into an existing microscopy facility, which includes a TEM and SEM, and is an integral component of research and educational programs.Layman Summary: Scanning probe techniques, in which a sharp tip is brought extremely close to a sample and information about the sample is gathered by dragging the tip across a surface, have become indispensable tools for the scientific community. One example is Atomic Force Microscopy (AFM), which can generate images of features on surfaces as well as maps of variation in materials properties across surfaces with extremely high (~nm) resolution. Many on-going research projects at Williams College require the use of an AFM. These include studies of the patterns which form in synthetic polymers which can be used to generate nanoscale features (smaller than features attainable through conventional photolithography in computer chip design), or which could be used for polymer-based solar cells and polymer-based drug delivery vehicles; research on the structure and organization of proteins in native biological membranes critical for photosynthesis in ecologically important organisms; studies of proteins involved in delivery of DNA into cells; and research on surfaces and comparison with light scattering experiments to improve techniques used in computer graphics.