Dr. Nicole Zacharia, a researcher in the TEES Mechanical Engineering Division, has received the prestigious Faculty Early Career Development (CAREER) Award from the National Science Foundation (NSF) for her proposal, "Electric Field Processing of Polyelectrolyte Complex."
The work to be conducted under this award is to examine phase behavior of solutions of synthetic polyelectrolyte complexes and to then use an electric field to manipulate these complexes in solution with the goal of depositing them as solids onto substrates. Synthetic polyelectrolytes, both strong and weak, that are typically used in layer-by-layer (LbL) assembly of polyelectrolyte multilayers (such as polyacrylic acid, sulfonated polystyrene, polyallylamine hydrochloride, and polyethylene imine) will be examined.
The first part of the work will be to determine phase diagrams for the complexes of different pairs of polyelectrolytes as a function of pH, solution ionic strength, molecular weight, and concentration. The thermodynamic behavior of these complexes is generally masked by kinetic considerations, and unraveling these components will be one goal. The next phase of the work will be to look at adsorption of complexes of different stoichiometries onto charged surfaces. The third phase of the work will be to compare this equilibrium adsorption to deposition onto charged surfaces under the influence of an electric field. Factors including ionic strength, dielectric constant of the solvent, and addition of other components such as metal nanoparticles will be examined. This process will eventually be generalized to look at the electrophoretic deposition of other types of soft matter such as micelles or hollow polyelectrolyte capsules.
The last phase of the work is to examine the solid materials created by this process. It is hypothesized that different stoichiometries and properties can be achieved through electric field manipulation as compared to equilibrium adsorption onto a surface.
Zacharia is also an assistant professor in the Department of Mechanical Engineering and the Materials Science and Engineering Program at Texas A&M University. She joined the Materials Division in the Department of Mechanical Engineering in 2009. She received her Ph.D. from Massachusetts Institute of Technology in 2007. From 2007 to 2009 Zacharia worked at the University of Toronto as a postdoctoral fellow in the departments of Electrical Engineering and Chemistry.