Paints are multi-component systems formulated to produce specific product properties. The rate and uniformity at which these coatings wet spread and coalesce into a film can be controlled by the constituents in the formulation. Depending on their end use, coatings can have four or more components in their mixture. Solid or higher-viscosity components consist of pigments used to obtain a specific color, and oil emulsions or latex components that provide film formation or coating properties. Both are mixed with a number of water-soluble materials, such as surfactants, silanes, viscosity modifiers, processing aids, color aids and polyelectrolytes, which can also be surface active. These water-soluble surface-active elements can affect the surface chemistry or interfacial behavior of the solid particle components. The soluble components play a vital role in the final film properties and color of a paint formulation, and can be studied using zeta potential.
Zeta potential is a physical property exhibited by any particle in suspension. It can be quantified using electrophoretic mobility (electrophoresis) measurement and adjusted to optimize coating formulations. Studying zeta potential results enables the building of relationships between the chemical composition of formulated coatings and the required final physical properties and color. Today, zeta potential is easy to measure and aids in predicting long-term stability and optimizing product properties.