469877 Mesoscale Particle-Based Model of Electrophoretic Deposition

Wednesday, November 16, 2016: 9:45 AM
Embarcadero (Parc 55 San Francisco)
Brian Giera, Chemical Engineering, University of California Santa Barbara, Santa Barbara, CA and Luis A. Zepeda-Ruiz, Chemistry and Material Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA

Electrophoretic deposition (EPD) describes the process in which field-driven particles accumulate at electrodes and assemble into layers. The majority of EPD models provide continuum level descriptions of mass deposition that inherently neglect particle-based interactions within the bulk suspension, growth front, and deposit. These inter-colloidal interactions are necessary to understand the underlying physics that govern particle rearrangement, defect formation, and the ultimate microstructure of the deposit. Here, we present and evaluate a particle-based model of colloidal suspensions that undergo electrophoretic motion[1] and deposition using an extensive set of mesoscale simulations that characterize experimentally relevant colloidal suspensions. The model accurately describes diffusive and electrophoretic motion of experimentally relevant colloidal suspensions. Since the model explicitly computes inter-colloidal interactions, it is uniquely poised to elucidate how deposition conditions influence defect structures and particle rearrangement within EPD colloidal crystals. We use the model to investigate how empirical parameters, such as electric field strength and electrolyte concentration, can be tuned in order to control the degree of colloidal ordering versus non-ordering that occurs during EPD. It is straightforward to configure the model to study how various preparations of the interface, e.g. a bare surface, a lattice of particles, an amorphous monolayer, etc., and also annealing schemes influence the deposit microstructure.

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

[1] Giera, B.; Zepeda-Ruiz, L. A.; Pascall, A. J.; Kuntz, J. D.; Spadaccini, C. M.; Weisgraber, T. H. Mesoscale Particle-Based Model of Electrophoresis. Journal of the Electrochemical Society. The Electrochemical Society 2015, pp D3030–D3035.

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