Zeta Potential measures the strength of net charge on particle and solid surfaces. The higher the potential magnitude, the stronger the surface interaction such as repulsion and attraction.
Covalent offers Zeta Potential measurements for a wide range of samples and applications. For particle applications, Electrophoretic light scattering (ELS) is most typically used. This method of analysis works by measuring the field-dependent particle movement: average particle speed is correlated to the strength of surface charge.
Zeta Potential on other forms of active surfaces (such as semiconductor wafers, membranes, fibers, pads, etc.) can be measured using the principles of flow-rate and pressure dependent charge dissociation. In these measurements, samples are typically mounted in a fixed geometry to create a channel through which the electrolyte flows. As it flows, the electrolyte will shear charges off the channel surfaces, producing a change in potential correlated to the sample’s Zeta Potential.
Both methodologies are rapid and time-efficient, and can provide valuable insights to assist product and process development.
What zeta potential measurement is great for:
Evaluate formulation stability in inks, paints, coatings, medicine, and personal care products
Surface adsorption and desorption behaviors of additives such as surfactant, anti-fingerprint coatings, slip agent, lubricant, enzyme
Surface kinetics of functional materials and modified surfaces such as filters, membranes, filtration system, and personal care products
Performance-related parameters such as pH stability, isoelectric point, ionic strength, temperature-dependence
Process tuning for chemical mechanical polishing (CMP)
INSTRUMENTS USED FOR Zeta Potential
Anton Paar Litesizer™ 500 for solution-state samples
The Litesizer 500 has been optimized to characterize nano- and micro- particles in dispersions and solutions. It includes advanced analytical tools able to distinguish between several particle sizes present within the same sample, and has highly accurate detector systems to facilitate parallel measurement of the refractive index of the material at the exact wavelength and temperature used during zeta potential measurement.
Anton Paar SurPASS™ 3 for solid-state samples
The SurPASS 3 is a highly adaptable, high-end zeta potential measurement tool for flow-dependent measurements of zeta potential in macroscopic solids (e.g. on polymer films, membranes, sensors, metalic sheets, etc). Outfitted with diverse measurign cells, the SurPASS can accomodate solids of virtually any geometry and scale, down to 25 microns in powder grain diameter. It also incorporates fully automated pH scans and highly time-sensitive kinetic monitoring of adsorption effects to provide a deep understanding of surface electrochemistry.