New techniques for measuring zeta-potential of colloidal system

Colloidal systems are used in different fields of science and industry. At present, colloidal systems and their properties are being actively studied. The stability of colloidal systems is the main characteristic. For example, stability is hindered by aggregation and sedimentation phenomena, which are driven by the colloid's tendency to reduce surface energy. The technique of electrophoretic light scattering allows us to measure zeta - potential of colloidal systems related to stability of systems. As compared with other methods (Doppler velocimetry, electrophoresis, optical microscopy, Raman spectroscopy), this technique has a short time for analyses, a small volume of the objects to be investigated and cheap equipment. Zeta-potential is used to characterize particle surface charge and to obtain information about their stability and surface interaction with other molecules. In this review, we focus on nanoparticle characterization. In our study, the new techniques for measurement of zeta-potential of colloidal system is realized on the basis of a total internal reflection prism where the free electrophoresis regime is set. The purpose of our work is to compare two types of sample cells and different techniques of measuring electrophoretic mobility and zeta-potential of colloidal systems. The silicon oxide spheres suspended in deionized water with a concentration of 25% and a diameter of 320 nm were used as a test sample. The results obtained in our study demonstrated the applicability of the method for the investigation of liquid solutions, including biological fluids, and a higher sensitivity as compared with standard measurements techniques in bulk measurements.