An effective zeta potential fitting model for sphere-plate interaction force in nanoparticle suspensions

The silica sphere-plate interaction forces in zirconia nanoparticle suspensions have been successfully measured to explain how negligibly charged silica microspheres can be stabilized through the addition of highly charged zirconia nanoparticles. However, the influence of nanoparticle volume fraction on the stabilization as well as how various forces (the attractive van der Waals force, repulsive electrostatic force, and depletion force) contribute to the total interaction force still remains unclear. Therefore, an effective zeta potential fitting model is developed to explain the experimental interaction force curves based on a variable effective Debye length and a measured effective zeta potential using a continuum assumption.