When Zeta Potential is Important

Almost all particulate or macroscopic materials in contact with a liquid acquire an electronic charge on their surfaces. Zeta potential is an important and useful indicator of this charge which can be used to predict and control the stability of colloidal suspensions or emulsions, for example. The greater the zeta potential the more likely the suspension is to be stable because the charged particles repel one another and thus overcome the natural tendency to aggregate. The measurement of zeta potential is often the key to understanding dispersion and aggregation processes in applications as diverse as water purification, ceramic slip casting and the formulation of paints, inks and cosmetics.

Zeta potential can also be a controlling parameter in processes such as adhesion, surface coating, filtration, lubrication and corrosion. Consequently, the presence or absence of charged groups on the surface of macroscopic materials such as hair, glass fiber, paper pulp, plastic films and refractories, as revealed by their zeta potentials can directly affect their performance and processing characteristics. Brookhaven offers you a choice of instruments to meet your needs in each of these fields.

Choose the ZetaPlus for measurements on particles ranging from a few nanometers to as large as 30 microns diameter. It uses electrophoretic light scattering and the Laser Doppler Velocimetry (LDV) method to determine particle velocity and, from this, the zeta potential. It also offers the option of particle size analysis in the same instrument.

If your suspended samples typically have very low mobilities because they are suspended in oils or organic solvents, or because they are in a fluid with high salt concentration (>~20mMolar) or just because they are near the iso-electric point (IEP) then you may require the 1000x sensitivity provided by our unique Phase Analysis Light Scattering ZetaPALS instrument.

For macroscopic samples --plates, films and fibres as well as particles larger than about 30 microns in diameter-- use streaming potential to calculate zeta potential. For more information on this subject, please contact our factory by clicking on "Contact Us" in the main menu bar.