Application of Ionic Liquids in the Electrophoretic Deposition of Oxide Layers

Abstract

Ionic Liquids (IL) are novel materials with a wide range of applications. The variable combination of organic cation and inorganic anion offers the possibility of tuning their properties. In the present investigation we test the application of different ionic liquids as charging agents for the preparation of stable oxide suspensions for direct use in electrophoretic deposition to produce oxide layers on different substrates. Main objective of these investigations was to prove that this substance class constitutes suitable additives for successful electrophoretic deposition (EPD). As one key parameter for the EPD process is the particle charge, a big part of our investigations involved the measurement of the zeta-potential of in alcoholic suspension under the influence of phosphonium and imidazolium based ionic liquids using a micro-electrophoresis measurement

Mesoscale Particle-Based Model of Electrophoretic Deposition

“…ionic strength, permittivity, and viscosity of the suspension as well as the electric potential difference between the surface of the colloid and suspension (termed the zeta-potential). Because of the vast material set inherent to colloidal suspensions, EPD has been demonstrated in systems of aqueous electrolytes, nonpolar solvents, , and ionic liquids that stabilize colloids composed of ceramics, graphene-related materials, nanometals, polymers, phosphors, or biological materials . EPD is central to numerous applications that include industrial coating, fabrication of supercapacitor electrodes and quantum-dot light-emitting devices, near-shape manufacturing of tubes or structured parts, and controlled growth of artificial opals .…”

Mesoscale Particle-Based Model of Electrophoresis

“…Colloids comprised of ceramics, 1 carbon nanotubes, 2 nanometals, 3 polymers, 4 phosphors, 5 and biological materials 6 undergo electrophoretic motion in response to an applied electric field that acts upon the charged interface between the particle and surrounding suspension. 10 In addition to the applied field strength, the electrophoretic velocity depends on the ionic strength, permittivity, and viscosity of the suspension as well as the potential difference between the surface of the colloid and suspension (termed the zeta-potential). 10 In addition to the applied field strength, the electrophoretic velocity depends on the ionic strength, permittivity, and viscosity of the suspension as well as the potential difference between the surface of the colloid and suspension (termed the zeta-potential).…”

“…Some examples of the suspension media are aqueous 7 and non-polar 8 solvents, liquid crystals, 9 or ionic liquids. 10 In addition to the applied field strength, the electrophoretic velocity depends on the ionic strength, permittivity, and viscosity of the suspension as well as the potential difference between the surface of the colloid and suspension (termed the zeta-potential). Electrophoresis is central to electrophoretic deposition (EPD) in which field-driven particles accumulate at electrodes or liquid-liquid interfaces 11 to form layers that are stabilized by shortranged van der Waals interactions.…”