Department of Chemistry

College of Science

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Current Activities

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The research in my group is organized around three main projects. These include: 1) nanoscale materials and devices, 2) nanotribology, and 3) biological surfaces and interfaces. The general theme of the work in my group is the development of custom engineered surfaces and interfaces. Much of this work involves the development of a fundamental (molecular level) understanding of the underlying chemistry and physics of the systems in question to afford rational approaches for improving current and developing new technologies.

Self-Organizing Nanoscale Materials and Devices

In this program we are interested in developing approaches for the design and assembly of nanoscale materials and devices for molecular electronic, photonic and sensor applications. In our work we utilize a combination of top-down and bottom-up approaches. The ability to control and manipulate materials on the nanoscale offers significant advantages in the development of future technologies. In much of our work, we take advantage of self-organizing materials for the design of robust structures, which can be manipulated and controlled through the engineering of specific inter-molecular forces and chemical interactions with surfaces. We combine self-assembly with soft-lithographic and scanned probe lithographic techniques to enable the design of nanoscale test architectures. These include confined molecular assemblies for molecular electronics, polymer-metal heterojunctions for organic electronics and nanoscale metallic structures for plasmonic devices.

Nanotribology

The details of friction and wear on the nanoscale are of significant consequence for a number of developing technologies including microelectromehanical systems (MEMS) devices. The generation of defects at surfaces in sliding contacts is the catalyst for the eventual wear of the materials. In this project we are investigating the wear of oxide surfaces at the nanoscale, including probing how local environment (such as the presence of water) impacts the formation and nucleation of defects at the atomic level. Associated with the investigations of friction and wear, we have developed force microscopy studies designed to directly probe the interactions at nanoscale asperities in sliding contacts using AFM. In contrast to the above studies on atomically smooth crystalline surfaces, this approach provides a means to evaluate adhesion and wear in true nanoscale asperity-asperity contacts, which more closely mimic the actual interactions found between real surfaces in contact. In fact, with sufficiently sharp tips, bond quantization and energetic exchange with solvent becomes visible.

Biological Surfaces and Interfaces

Plant Surfaces and Interfaces: The aerial surfaces of the leaves and fruits of higher plants consist of a cuticular membrane that occupies approximately the outer 0.1 µm to 10 µm of the plant surface (depending on species). The membrane is composed of a variety of lipid compounds mostly (~ C₃₀ aliphatic based hydrocarbons) for waterproofing and the biopolyester cutin, which functions as a structural support. A thin layer of epicuticular lipids coats the outer surface of the cuticle, while intracuticular lipids (predominantly fatty acid based) are embedded within the cutin matrix. The cuticle controls the plant?s interactions with the environment, protects against water loss and functions as the plants primary protective barrier against pathogenic attack. We employ a combination of scanned probe microscopy and solid-state NMR spectroscopy to investigate the thermo-mechanical properties of plant protective membranes at the nanoscale. The AFM and NMR offer complementary views of these materials as the AFM affords 3-D visualization and surface mechanical properties via nanoindentation, while NMR allows for the molecular dynamics and bulk mechanical response to be probed. Surface and bulk elasticity studies are tied together by solid-state NMR measurements of the associated changes in the bulk cuticle molecular dynamics from relaxation experiments and two-dimensional ¹H-¹³C wide-line separation (WISE) NMR. These NMR studies provide site-specific data on cuticular flexibility on both the MHz and kHz frequency scales. Lastly, we are employing lateral force AFM measurements for the analysis of lipid phase transitions on plant surfaces. Measurement of the lateral force as a function of temperature allows one to probe the ?drag? on the tip, as the lipids pass through a phase transition.

Nanoscale Protein Patterning: A new project to our group is the development of methods for the patterning of proteins on surfaces. Research in bioassays has rapidly moved to smaller scales in recent years and there is a significant need to be able to engineer interfaces, which are capable of selectively binding proteins in specific orientations to achieve highly sensitive assays. In this project automated scanned probe lithography (SPL) is employed for the rapid design of protein patterns on surfaces. The ability to precisely position bioactive molecules on surfaces allows for the details of structure and function of even single molecules to be evaluated. The research in this project will be developed in two directions: first, the development of ultra sensitive assays with detection by either AFM or single molecule fluorescence; second, the application of patterned anchoring of proteins to facilitate force measurements of both biomolecules and biological assemblies by AFM.

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Selected Publications

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J.M. Helt and J.D. Batteas, "Wear of Mica in Aqueous Solutions: Direct Observation of Defect Nucleation by AFM", Langmuir 21 (2005) 633.

J.D. Batteas and R.E. Stark, "Surface and Interfacial Studies of Plant Biopolymers by SPM and NMR", Woodhead Publishing Ltd., Cambridge, UK (in press).

J.M. Helt, C.M. Drain and J.D. Batteas, "A Benchtop Method for the Fabrication of Nanowires on Polymer Surfaces", J. Am. Chem. Soc. 126 (2004) 628.

C. Gonzalez, Y. Simón-Manso, J.D. Batteas, M. Marquez, M. Ratner and V. Mujica, "A Quasi-molecular Approach to the Conductance of Molecule-Metal Junctions: Theory and Application to Voltage-Induced Conductance Switching", J. Phys. Chem. 108 (2004) 18414.

R.W. Carpick and J.D. Batteas, "Scanning Probe Studies of Nano-Scale Adhesion Between Solids in the Presence of Liquids and Monolayer Films", book chapter, in Springer Handbook of Nanotechnology Handbook, B. Bhushan (ed.), Springer-Verlag, Heidelberg, Germany, 605-629, 2004.

J.M. Helt and J.D. Batteas, "Mica Surfaces: Charge Nucleation and Wear." In Dekker Encyclopedia of Nanoscience and Nanotechnology, James A. Schwarz, Cristian I. Contescu, and Karol Putyera, Eds.; Marcel Dekker, Inc.: Vol 3: 1947-1966, New York, 2004.

T. Milic, J.C. Garno, G. Smeureanu, C.M. Drain, J.D. Batteas, "Surface Organization of Porphyrin Tetrameric Arrays with Peripheral Alkyl Chains", Langmuir 20 (2004) 3974.

C.M. Drain, G. Smeareanu, J.D. Batteas, S. Patel. "Self-assembled Porphyrin Arrays on Surfaces", In Dekker Encyclopedia of Nanotechnology, J.A. Schwartz, C.I. Contescu, K. Putyera, Eds.; Marcel Dekker, Inc.: Vol 5. 3481-3502. New York, 2004.

X. Gong, T. Milic, C. Xu, J.D. Batteas, C.M. Drain, "Preparation and Characterization of Porphyrin Nanoparticles", J. Am. Chem. Soc. 124 (2002) 14290.

T. Milic, N. Chi, D. Yablon, G. Flynn, J.D. Batteas and C.M. Drain, "Controlled Hierarchical Self-Assembly and Deposition of Photonic Materials", Angewandte Chemie 42 (2002) 2117.

C.M. Drain, J.D. Batteas, G.W. Flynn, T. Milic, N. Chi, D. Yablon and H. Sommers, "Designing Supramolecular Porphyrin Arrays that Self-Organize into Nanoscale Optical and Magnetic Materials," Proceedings of the National Academy of Sciences 99 (2002) 6498.

A.N. Round, B. Yann, S. Dang, R. Estephan, R.E. Stark and J.D. Batteas, "The Influence of Water on the Nanomechanical Behavior of the Plant Biopolyester Cutin as Studied by AFM and Solid-State NMR", Biophysical Journal 79 (2000) 2761.