Zeta Potential Measurements

Zeta potential measures the charge on the surface of solid powder particles in suspension. It is the measure of the electrostatic repulsion or attraction between particles and is used as the best indicator for the stability of dispersions.

High surface charge encourages inter-particle repulsion and so a stable, deflocculated and usually low viscous suspension. Conversely low surface charge encourages flocculation and instability, which is usually associated with thick suspensions.

Apart from affecting the flocculation/deflocculation behaviour of suspension, particle charge (i.e. zeta potential) also determines the ability of the particle to interact with soluble ions, polymeric species etc.  So, in cases where the measured zeta potential is undesirable, surfactants, pH change or electrolyte additions can be used to alter and optimize suspension properties

Benefits that can be expected from zeta potential of powders / suspensions are:

• Improved suspension / emulsion stability and so lifetime
• Higher “down-stream” yields (in products made from suspensions)
• Superior end-product properties via a control of bulk or coating microstructure at the suspension stage
• Faster processing of suspensions
• Fast introduction of new products and formulation.

Typical Applications

• Identification of processing issues involving suspensions, i.e. casting, filtering, pumping, spraying, spinning, centrifuging, general liquid solid separation
• Batch to batch dispersion uniformity
• Aggregation and ageing problems
• Appraisal of new surfactants / additives
• Benchmarking of products
• End product performance
• Identification of new QA / QC procedures
• Validation of established QA / QC procedures.

Typical Industries using Zeta Potential

• Aerospace
• Automotive
• Materials
• Minerals
• Ceramics and Refractories
• Healthcare
• Medical Devices
• Electronics.