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Associate professor |
Education
B.S., Appalachian State University, 1994
Ph.D., University of New Orleans, 1999
National Research Council Fellow, Naval Research Laboratory, Washington, D.C., 1999-2000
Research Chemist, Naval Research Laboratory, Complex Materials Section, Washington, D.C., 2000-2004.
Research interests
Recent decades have seen a flurry of promising methods for nanoparticles synthesis. My research continues to be on the forefront of nanoparticle synthesis, focusing primarily on mixed-metal iron oxide (ferrites) and metallic iron nanoparticles. While much my early work focused on reverse micelle techniques, we have expanded our synthesis to include many other synthetic techniques such as precipitation reactions, and polyol or thermal decomposition. Research in my laboratory is focused on three main areas.
1. Biomedical applications
Ferrite materials are ideally suited for a wide variety of applications ranging from power electronics and electromagnetic filtering to biomedical applications. While enhanced ferrites would have a major impact on electronic applications, probably the greatest impact would be in the biomedical applications like Magnetodynamic therapy (MDT), specifically magnetic hyperthermia where an AC magnetic field induces localized heating used to destroy targeted cells. MDT applications research for the past several years has focused primarily on instrumentation optimization chiefly because adequately stable nanoparticles have been lacking. The majority of research on MDT utilizes frequencies closer to 400 KHz since higher frequencies can stimulate nerves.
We however are taking a higher risk approach and trying to develop enhanced ferrites which would operate at MRI frequencies or higher. With our experience in higher frequency applications, we could produce functionalized core-shell enhanced ferrites with the potential to absorb significant AC energy at 100 MHz, the operating frequency of the MRI, making it possible to perform new MDT treatments with existing MRI equipment. This proposed coupling of MDT with pre-existing MRI facilities could have a revolutionary impact on cancer treatment. However there are many obstacles to overcome before MRI coupled MDT is possible or could even be evaluated. However given the potential impact this would have on oncological diagnosis and treatment it is worth the research time.
2. Growth mechanisms
With the wide range of reactions, there are several different often-competing mechanistic theories. Several attempts to reconcile the different theories have driven the need to create a comprehensive model of nanoparticle growth and nucleation. The initial models were based on population dynamics of the small systems and focused more on the changing concentration of products and reactants. Nucleation and growth were explained via the traditional LaMer model of nucleation followed by Ostwald ripening and left out of the model for simplicity. With more computing power, new Monte Carlo models have been developed which take into account growth and nucleation steps but also include many other steps such as the autocatalysis, polydispersity and the surface energies. These models while intriguing have found limited applicability due to a lack of available experimental data. We are seeking to study systems where we can add our experimental expertise in expanding the available models and create new ones. This will allow for the faster discovery of new magnetic materials as well as greater control over the size and shape of the nanoparticles. The size and shape of the nanoparticle dramatically impact the electronic and magnetic properties.
3. Nanomanufacturing
Nanoparticles have the potential to have significant impact on a number of different areas including application as nanocatalysts for chemical synthesis. A significant problem that has been identified is the need to transition bench-scale research to larger-scale production for real world applications. To achieve this, fundamental knowledge of the factors that govern nanoparticle synthesis is required so that process parameters can properly be controlled during scale-up.
References
Updated January 2011
1. Pettigrew, K. A.; Long, J. W.; Carpenter, E. E.; Baker, C. C.; Lytle, J. C.; Chervin, C. N.; Logan, M. S.; Stroud, R. M.; Rolison, D. R. “Nickel Ferrite Aerogels with Monodisperse Nanoscale Building BlocksThe Importance of Processing Temperature and Atmosphere” Nano Letters 2008, 2, 784-790. 2. Brewer, G.; Brewer, C.; White, G.; Butcher, R. J.; Viragh, C.; Carpenter, E. E.; Schmiedekamp, A. “Syntheses and characterization of iron(II) and iron(III) complexes of a tripodal ligand derived from tris(2-aminoethyl)methane” Inorganica Chimica Acta 2009, 362, 4158-4166. 3. Shultz, M. D.; S.Calvin; Gonzalez-Jimenez, F.; Mujica, V.; Alleluia, B. C.; Carpenter, E. E. “Gold-Coated Cementite Nanoparticles: An Oxidation-Resistant Alternative to a-Iron” Chemistry of Materials 2009, 21, 5594-5600. 4. Alvarado, L.; Brewer, G.; Carpenter, E. E.; Viragh, C.; Zavalij, P. Y. “Use of acid-base and redox chemistry to synthesize cobalt(III) and iron(III) complexes of a partially deprotonated triprotic imidazole-containing Schiff base ligand: Hydrogen bound 1D linear homochiral and zig-zag heterochiral supramolecular complexes” Inorganica Chimica Acta 2010, 363, 817-822. 5. Carroll, K. J.; Calvin, S.; Ekiert, T. F.; Unruh, K. M.; Carpenter, E. E. “Selective Nucleation and Growth of Cu and Ni Core/Shell Nanoparticles” Chemistry of Materials 2010, 22, 2175-2177. 6. Harris, V. G.; Chen, Y.; Yang, A.; Yoon, S.; Chen, Z.; Geiler, A. L.; Gao, J.; Chinnasamy, C. N.; Lewis, L. H.; Vittoria, C.; Carpenter, E. E.; Carroll, K. J.; Goswami, R.; Willard, M. A.; Kurihara, L.; Gjoka, M.; Kalogirou, O. “High coercivity cobalt carbide nanoparticles processed via polyol reaction: a new permanent magnet material” Journal of Physics D-Applied Physics 2010, 43, 165003. 7. Rivers, J. H.; Carroll, K. J.; Jones, R. A.; Carpenter, E. E. “A copper-polyol complex: [Na2(C2H6O2)6][Cu(C2H4O2)2)]” Acta Crystallographica Section C-Crystal Structure Communications 2010, 66, M83-M85. 8. Zhang, W.; Zheng, Y.; Orsini, L.; Morelli, A.; Galli, G.; Chiellini, E.; Carpenter, E. E.; Wynne, K. J. “More Fluorous Surface Modifier Makes it Less Oleophobic: Fluorinated Siloxane Copolymer/PDMS Coatings” Langmuir 2010, 26, 5848-5855. 9. Zheng, Y.; Zhang, W.; Gupta, M.; Kankanala, S.; Marks, C.; Carpenter, E.; Carroll, K.; Wynne, K. J. “Poly(bis-2,2,2-trifluoroethoxymethyl oxetane): Multiple Crystal Phases, Crystallization-Induced Surface Topological Complexity and Enhanced Hydrophobicity” Journal of Polymer Science Part B-Polymer Physics 2010, 48, 1022-1034. Ward, K. W.; Carpenter, E. E. Portable oxygen generator, Virginia Commonwealth University, 2007. Ward, K. W.; Carpenter, E. E. Novel means to provide nonpulmonary oxygenation and improve tissue oxygenation, Virginia Commonwealth University, 2006. Carpenter, E.E.; Harris, V. G. Fluorescent-magnetic nanoparticles with core-shell structure, 2004, US Patent 7235228. Kurihara, L.K.; Carpenter, E.E. Low temperature diol processing of fine metallic particles and coatings, 2002, US Patent 7033416. Carpenter, E.E.; O’Connor, C. J.; Khumbar, A. Synthesis of core-shell nanoparticles via micro-emulsions, 1999 US Patent 6773823. Books, Book Chapters LaLena, J.N.; Cleary, D. A.; Carpenter, E.E.; Dean, N.F. Inorganic Materials Synthesis and Fabrication. John Wiley and Sons: New York, NY, 2008. Morrison, S.A.; Harris, V.G.; Carpenter, E.E. Chemistry and Physics of Doped Mixed Metal Ferrites Nanoparticles, In Doped Nanomaterials and Nanodevices; Chen, W., Ed.; American Scientific Press: 2008; Vol. 5, 87-96. Willard, M.A.; Kurihara, L.K.; Carpenter, E.E.; Calvin, S.; Harris, V.G., Chemically prepared magnetic nanoparticles. In Encyclopedia of Nanoscience and Nanotechnology; Nalwa, H.S., Ed 2004, 2, 815-848.
Updated: 01/19/2012 |
