(420e) Direct Numerical Simulations of Colloidal Assembly by Electrophoretic Deposition

Motivated by applications in material nanomanufacturing, we perform direct numerical simulations of electrophoretic deposition (EPD) of colloidal suspensions, with the aim of developing a quantitative model of the EPD process and of helping the design and optimization of experiments. A simulation method is developed to model the full deposition process that captures linear electrophoresis, dipolar interactions, electrostatic repulsion and van-der-Waals interactions (based on DLVO theory), Brownian motion, as well as electric and hydrodynamic interactions with the electrodes. Using a fast algorithm, suspensions of up to 5,000 particles are simulated, and results are reported for the final deposit microstructure as a function of effective electric Peclet number, strength of van-der-Waals interactions, Debye layer thickness, and suspension volume fraction. The final microstructure of the deposits is characterized by calculating radial distribution functions, distributions of coordination numbers, and Voronoi diagrams, and results are analyzed in the light of recent experimental observations. We also investigate the use of patterned electrodes and the influence of boundary conditions for the manufacturing of three-dimensional deposits of controlled shape and microstructure.