Electric-field-induced aggregation in dilute colloidal suspensions

Abstract

Electric-field-induced chain formation in dilute, non-aqueous suspensions of sterically stabilized, 1 µm poly(methyl methacrylate)(PMMA) latices are investigated. Optical microscopy and digital image analysis provide the chain-length distribution. We find that the particles carry a charge sufficient to inhibit field-induced aggregation. Equilibrium predictions of chain aggregation incorporating a screened Coulombic repulsion and field-induced dipole attraction agree well with experimental observations near the onset of aggregation; chain formation becomes diffusion limited above the threshold field strength.