In this informative session, Dr Hannah Buckland demystifies zeta potential and shows how electrophoretic light scattering (ELS) turns particle motion into insightful data that guides decision making from product formulation through to quality control. Starting with why zeta potential matters for dispersion stability, she walks through the electrical double layer (Stern layer, diffuse layer, slipping plane), the balance of attractive and repulsive forces, and practical routes to achieving stability (steric vs. electrostatic).
Drawing on her deep expertise in Zetasizer, she explains how light scattering and electrokinetic theory are combined to determine electrophoretic mobility, which we then convert to zeta potential.
Key takeaways
- Zeta potential is a key indicator of formulation stability. Large magnitude (±) values typically correlate with stronger electrostatic repulsion and more stable dispersions.
- Zeta potential is the potential at the slipping plane within the electrical double layer – it's not a fixed property of the particle alone.
- Environment controls charge: pH and ionic strength compress or expand the double layer, shifting measured zeta potential and stability.
- ELS measures mobility under a known field – the Zetasizer Advance converts this measurement to zeta potential in ZS Xplorer software.
- Cell selection, field strength, and field reversal help reduce artefacts such as electrode polarization.
- Applications are broad: Pharmaceuticals & personal care, food, pigments/coatings, and water treatment all use zeta potential to finetune stability or, in some cases, intentionally drive coagulation.
Key Quotes
“Zeta potential is a way to quantify the electrostatic repulsion or attraction between particles—and a practical handle on stability.”
“A single particle doesn’t have one zeta potential in all media; it depends on the dispersant, pH, and ionic strength.”
“We reverse the field during measurement to minimize electrode polarization and maintain data quality.”
Tools & technologies mentioned
Resources & further learning
- Explore the full series, Mastering Light Scattering Techniques: Essential Concepts for 2025
- Visit our Zetasizer content hub
발표자
- Hannah Buckland - Applications Specialist, Malvern Panalytical
Based at Malvern Panalytical’s UK headquarters, Dr Hannah Buckland works as an Applications Specialist for the Mastersizer and Zetasizer product lines. Her interest in particles was sparked during a PhD in volcanology and has since broadened to the diverse challenges of particle characterization in sectors ranging from biopharma and food to advanced and primary materials. Since December 2023, she has delivered proof-of-principle analyses, led instrument demonstrations, trained customers, and provided hands-on technical support.