Characterization of Colloidal Particles Using Electrical Impedance Spectroscopy in Two-electrode System with Carbon Probe

The colloidal particles have an electrical double layer associated with their surfaces when suspended in an aqueous medium. Under the influence of an alternating electric field, an induced electrical dipole moment can be formed due to the polarization of the electrical double layer. The electrical impedance spectroscopy (EIS) measurement can record the complex impedance, conductivity, relaxation frequency and phase angle caused by the polarization of the electrical double layer. These impedance parameters are in relation to particle characteristics, for example, the particle size. The research about particle size effect on electrical impedance spectra was carried out in a four-electrode system and the result indicated that impedance parameters shows a capability for characterizing the particle size. This paper reports the experimental results from electrical impedance spectroscopy measurements on silica suspensions in a two-electrode system with carbon probe. The main aim is to study the particle size effect on impedance parameters, especially the relaxation frequency and phase angle, to compare the data with those obtained from a four-electrode system with stainless steel electrodes and verify the capability for characterizing colloidal particles in different electrode systems. The particle size effect on the relaxation frequency and impedance phase angle was studied in two different electrode systems and a similar tendency can be observed. It indicates that the capability of impedance parameters for particle characterization is not limited in a four-electrode system, but commonly applicable in different electrode systems.