Electrophoretic deposition (EPD) process is frequently used to produce thin layers of nanomaterials. In particular, pulsed deposition method has allowed bubble?free deposits by EPD from water-based suspensions [1]. Although this strategy is proving to be effective, the precises roles of EPD parameters are still not fully understood to assure the good quality and reproducibility of the deposits. That is why the deposition conditions are most of the time obtained by empirical methods. In this study, we developed a modeling approach supported by experimental feedback in order to better understand EPD process in aqueous medium especially in pulsed-dc regime.
 
Monodisperse silica nanoparticles in aqueous suspension served as a model system. The influence of EPD parameters on deposition rate was first studied in dc condition and then in pulsed-dc to limit electrolysis. In the meantime, experimental results were confronted to a particle transport model developed by Finite Element Method (FEM) on the basis of previous work in organic medium and in dc regime [2]. Our results demonstrate that electrochemical reactions of water are responsible of pH modification at electrode surface and are limited by application of pulsed deposition method in specific frequency and duty cycle ranges. This last observation was supported by preliminary simulations of pH relaxation after one pulse time.
 
[1] J. Am. Ceram. Soc. 2008, 91, 3154?3159
[2] J. Phys. Chem. B 2013, 117, 1702?1707