Colloidal Probe AFM Measurements of the Electrophoretic Force

Colloidal probe atomic force microscopy is a very useful tool in the study of colloidal interactions. Although this technique has been applied to study interactions between a particle and a polarized electrode during electrodeposition, it has never been used to study interactions in high electric fields as encountered in electrophoretic deposition. In this work, a preliminary study was undertaken to verify whether colloidal probe AFM could be used to measure the electrophoretic force on a particle. It was found that the electrophoretic force could be detected by colloidal probe AFM under certain circumstances. In order to prevent that the contribution of the cantilever on the measurement of the electrophoretic force becomes large, the charge on the cantilever should be small compared to the charge of the particle, which is attached to the cantilever. Moreover, the area of cantilever surface which is oriented parallel to the electric field should be small to minimize the contribution of the cantilever.