Contract Analysis | Paints and Coatings | Zeta potential

At our applications lab we do several analysis. We´d like to share an interesting example with you.


Pigments are designed and produced to be insoluble particles used to impart colour in a variety of materials. The diverse range of its chemistries, the end use requirements, and the broad range of colours available create a challenge for chemists when incorporating them, being stability and settling one of the many factors to consider. The first steps in the pigment dispersion process are wetting and separation of the pigment. However, if the pigment dispersion is not properly stabilized, flocculation will result.

One of the main mechanisms to obtain pigment stabilization is charge repulsion, in which particle surfaces with like charges repel each other. Properly stabilized pigment dispersions prevent flocculation and agglomeration.

Zeta potential serves as a reference as to how stable the formula will be. Pigment dispersions with a zeta potential between +30 mV and -30 mV have a high probability of being unstable.

In this study, zeta potential was measured by Electrophoretic Light Scattering. Sample was a water dispersion of a pigment used in the automotive industry. Results obtained (image 1) are compatible with a stable dispersion as average zeta potential is -42,3 mV.

The equipment used in this work was Zetasizer from MalvernPanalytical and sample cell was a folded capillary cell. For more information, please click here.

Analysis reports can be prepared in English (default), Portuguese or Spanish.

Other services can be requested on demand. They include analytical methods development and validation, route cause analysis support, reverse engineering support and technical consultancy in material characterization.

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