Decisive influence of colloidal suspension conductivity during electrophoretic impregnation of porous anodic film supported on 1050 aluminium substrate

Abstract

The present paper studies the influence of suspension conductivity on the electrophoretic deposition (EPD) of nanoparticles inside a porous anodic aluminium oxide film. It is shown that an increase in the suspension's conductivity enhances impregnation of the anodic film by the nanoparticles. Two mechanisms are seen to promote the migration of particles into the pores. Indeed an increase in the suspension conductivity leads on the one hand to a strengthening of the electric field in the anodic film and on the other hand to a thinning of the electric double layer on the pore walls. The results of our study confirm that colloidal suspension conductivity is a key parameter governing the electrophoretic impregnation depth.

Nonaqueous Sol–Gel Synthesis of Anatase Nanoparticles and Their Electrophoretic Deposition in Porous Alumina

“…Complementarily, they showed that faster deposition was obtained under higher electric field but resulted in the formation of nanotubules. Similar conclusions were attained by Fori et al, , who successfully performed the electrophoretic deposition on the barrier layer of anodized aluminum using SiO 2 colloidal dispersion in isopropyl alcohol (IPA). They emphasized that higher electric field and dispersion conductivity improves the impregnation and flocculation of the nanoparticles in the pores.…”

Immobilization of colloidal particles into sub-100 nm porous structures by electrophoretic methods in aqueous media

“…Electrophoresis approaches using porous substrates based on anodic aluminium oxide (AAO) [20][21][22] or graphite [23] had been already reported with using non-aqueous media.…”

Innovating pulsed electrophoretic deposition of boehmite nanoparticles dispersed in an aqueous solution, into a model porous anodic film, prepared on aluminium alloy 1050

“…Fori et al [18,19] responded to this issue by using an organic based dispersion of SiO 2 particles, leading to complete filling of the pores, thus successfully avoiding side reactions such as solvent electrolysis. Despite the difficulties encountered in using an aqueous medium for EDP, Kusdianto et al [20] reported the potential to fill pores of less than 1µm in length using a pulsed electric field to limit water splitting, while Escobar and al.…”

“…Fori et al [19] have already shown (although in organic media), that to obtain the migration of particles into the pores it was necessary to increase the conductivity of the solution: the interaction between particles and pore walls is reduced thanks to the electric double-layer compression of both the pore/electrolyte and the particle/electrolyte interfaces. They also demonstrated that increasing conductivity of the dispersion led to focusing the electric field on the anodic film region, improving particle impregnation throughout the anodic film.…”