Directed Self-Assembly of Colloidal Model Systems on Charge-Selective Surfaces in External Electric Fields: Theory and Numerical Analysis

Abstract

Membrane electrophoretic deposition has a long-established reputation in delivering high quality nanoparticle compact and coating solutions in the field of high performance nanoparticle architectures made from aqueous nanoparticle suspensions. Although for a long time, it has been common practice in nanoparticle science and particle-based nanotechnology to use membrane electrophoretic shaping of nanoparticles, little is known about long-range electrohydrodynamic manipulation of the engineered assembly of colloidal particles at the nanoscale. Here, we analyze the interfacial field-induced flow of a strong electrolyte and its implications for the directed self-assembly of colloidal nanoparticles on nonuniform charge-selective ion-exchange membrane surfaces as well as on conducting microelectrodes imposed to electrophoretic deposition boundary conditions. Numerical calculations of the vortex streamlines are derived for the case of extreme diffusion limitation, concentration polarization near the limiting current, and induced electric forces acting upon the residual space charge. The system is modeled by coupled mass balances, Ohmic law, Navier-Stokes, and Nernst-Planck equations. Particularly, numerical calculations under bulk electroconvection conditions show that the latter provides an efficient intrinsic interfacial mechanism capable of accounting for the experimentally observed local electrophoretic deposition behavior of nanoparticles at ideal permselective membranes with nonplanar periodic charge discontinuity and metal microelectrodes.

Zinc diketonates as single source precursors for ZnO nanoparticles: microwave-assisted synthesis, electrophoretic deposition and field-effect transistor device properties

“…S8) allow characterization of the granular microcrystalline structure of the formed ZnO film. Although oriented attachment [35][36][37] seems to occur in areas close to the surface, the overall film consists of randomly oriented ZnO crystallites.…”

Advances in Microscale and Nanoscale Mechanisms of Electrophoretic Deposition in Aqueous Media

“…It has to be noted that this model is based on a charge discontinuity in the area of the membrane pore without the influence of any external potentials. A detailed description of the FEM approach is given anywhere else [6,7].…”

How Do Colloidal Nanoparticles Move in a Solution under an Electric Field?: In Situ Light Scattering Analysis

“…10 However, the deposition mechanism is not fully understood, although investigating NP dynamics under an electric field is crucial to uncovering the origin of NP movements in a solution and enhancing the deposition efficiency. 19 Typically, liquid cell transmission electron microscopy is a widely used technique for observing colloidal NP processes such as growth, 20 chemical transformation, 21 and diffusion. 22 However, observing NP dynamics using a liquid cell transmission electron microscope under an electric field is less favored because the NPs travel macroscopically during EPD from micrometers to centimeters.…”

“…Kang et al demonstrated that the type of nonpolar solvent determines the morphological characteristics of EPD products . However, the deposition mechanism is not fully understood, although investigating NP dynamics under an electric field is crucial to uncovering the origin of NP movements in a solution and enhancing the deposition efficiency …”