Role of the electric field affected zone (EFAZ) on the electrophoretic deposition of TiO2 nanoparticles under symmetric low-frequency AC electric fields.

In the present study, electrophoretic deposition (EPD) of TiO(2) nanoparticles under the application of symmetric AC fields was investigated. In the first step, EPD of TiO(2) nanoparticles under a DC field at 50 V resulted in the particles' deposition on one electrode, consistent with conventional EPD principles. However, no deposits were formed on any of the electrode surfaces for symmetric sinusoidal waves at 1 Hz. In this case, enhancing the electric field strength through the application of higher potentials was considered to extend the electric field affected zone (EFAZ) in front of the electrode, increasing the particles' opportunity to deposit. A kinetic model was then derived based on the Hamaker approach to calculate the deposited mass under an AC electric field. Although this model was found to be in agreement with experimental results at 1 Hz above 200 V, some deviation was detected at lower voltages. This trend shows that there is a threshold field strength below which EFAZ is not wide enough to let particles deposit under an AC electric field.