Electrodispersion Processes

This research examines the use of high-intensity-pulsed electric fields for drop size control in reactive water-in-oil emulsions that result in the formation of single- and multicomponent hydrous metal oxide particles or calcium alginate microspheres with diameters of 0.1- to 10 mm. Fundamental studies include experimental and computational investigations of the (1) electrohydrostatics and electrohydrodynamics of atomization processes in liquid-liquid systems and (2) mass transfer/precipitation or gelation dynamics in the microdroplet environments to better control the morphology of the microspheres.

Experiments involve the use of an electrodispersion precipitation reactor, a high voltage power source, a high speed imager (up to 8000 images per second), and several characterization tools (SAXS, USAXS, Light Scattering, Electrophoresis, FTIR and NMR). Finite element methods and hybrid finite element-boundary element methods are employed to solve the governing electrohydrostatic and electrohydrodynamic equations.

Dynamics of Nanophase Formation

The hydrolysis and condensation of silicon alkoxide and metal alkoxide are employed to produce nanostructures and monodisperse nanoparticles. Small-angle X-ray scattering (SAXS), ultra-small-angle X-ray scattering (USAXS), light scattering, NMR and FTIR spectroscopy are used to probe the dynamics of nanophase formation to elucidate the mechanism(s) controlling the structure and size of the initial nanophases that are formed.

Impaction and Drying of Hydrosol and Organosol Drops on Smooth and Porous Substrates

This research focuses on determining the effect(s) of colloidal particles on the impaction, spreading and drying of drops on various substrates. High spread imaging is used to monitor drop oscillations and the spreading dynamics. Single drops and multiple drops from ultrasonic and electrostatic spray nozzles are investigated. The finite element method is used to solve the fluid mechanics and mass transfer equations that govern the impaction, spreading and drying of these drops on the substrate.

Environmental Control Technology

The main thrust of this research is to develop models to guide the development of novel electrokinetics techniques for the removal of ions and charge-carrying contaminants from concrete and other porous media. Algorithms are being developed to accurately account for the complex chemistry of the porous media and the constituents in the liquid phase.

Materials Synthesis Using Biotemplates

Metals (gold, platinum, palladium and nickel) are deposited on the surface of self-assembed biological structures such as tobacco mosaic virus (TMV). Discrete and continuous nanometric deposits have been achieved on wild-type and genetically engineered TMV. The future application of the metal coated TMV include sensors, batteries and nanocircuits.

"Decoupling and Elucidation of Surface-driven Processes during Inorganic Mineralization on Virus Templates," O. Adigun, G. Novikova; E. L Retzlaff-Roberts; B.S. Kim; J. T Miller, L.S. Loesch-Fries, and M. T. Harris, Journal of Colloid and Interface Science (Accepted for publication July 2016)

"BSMV as a Novel Biotemplate for Palladium Nanomaterial Synthesis," O. Adigun, E.L. Retzlaff-Roberts; G. Novikova; L. Wang; B.S. Kim; J. Ilavsky; J.T. Miller, L.S. Loesch-Fries, and M.T. Harris, Langmuir, 33(7), 1216-1724, DOI 10.1021/acs.langmuir.6b03341 ( 2017).

"Silver Nanowire Synthesis in a Continuous Millifluidic Reactor," S. Hemmati, D.B. Barkey, L. Eggleston, B. Zukas, N. Gupta, and M.T. Harris, Electrochemical Society Journal of Solid State Science and Technology, 6(4), 144-149 (2017) .

"Scaling Laws and Dynamics of Bubble Coalescence," C.R. Anthony, P.M. Kamat, S.S. Thete, J.P. Munro, J.R. Lister, M.T. Harris, and O.A. Basaran, Physical Review Fluids, 2(8), 083601-1 - 083601-24 (2017).

"Bio-inspired Systems for Fabricating Nanocircuits, A Case Study," O. Adigun, A. Freer, B. Boudouris, L. Mueller, C. Gilpin and M.T. Harris, Chapter 8: Nanotechnology Commercialization, pp. 285-304, Wiley (2017).

"The Importance of Gravity in Droplet Evaporation: A comparison of Pendant and Sessile Drop Evaporation with Particles," N. Devlin, K. Loehr, and M. T. Harris, AIChE J., 62(3), 947-955 (2016).

"Mechanistic Study of the Hydrothermal Reduction of Palladium on the Tobacco Mosaic Virus," O. Adigun, A. S. Freer, J. T. Miller, B. Kim, L. S Loescsh-Fries, and M. T. Harris, Journal of Colloid and Interface Science, 450, 1-6 (2015).