Stability Matters: Zeta Potential and Rheology in Dispersion Control

This webinar will be presented in two parts discussing the different techniques available to make a what is consider a stable dispersion.

The first part considers that industries involved in the production of colloidal dispersions, the long-term stability is an important characteristic of the sample. Zeta potential is a measure of the electrostatic repulsion that exists between particles and can be used to predict dispersion stability. This talk will discuss what factors influence zeta potential and how it can be measured. Some application examples will be presented to demonstrate the use of zeta potential measurements in understanding and optimizing dispersion stability.

Then we consider in the second part the different when considering “larger” non-colloidal particle dispersions (typically above ~1um) where classic DLVO theory / zeta potential alone cannot be used to prevent sedimentation. Instead “rheology” can be used to make a kinematic or thermodynamic stable system; two different mechanisms with different benefits depending on the sample of interest. A few practical examples with measurement data will be shown to demonstrate these concepts. 

Presenters:

Dr. Mike Kaszuba, MRSC CChem, Technical Support Manager, Malvern Panalytical Ltd 

Dr. Adrian Hill, Kriechen (Rheologie)Creep is one of the earliest “controlled stress” rheometer tests that quite literally “creeps” the material, i.e. we measure over a relatively prolonged period the small movement (the creep defined as creep compliance, J) of the sample by applying a small constant stress.Rheology Specialist, NETZSCH Thermal Instruments UK Ltd.