Zeta Potential

Zeta Potential
Surface zeta potential of SiN wafers after cleaning by hydrofluoric acid, displayed as a function of pH.

Zeta potential measures the strength of net charge on particle and solid surfaces. The higher the magnitude of this potential, the stronger the surface interactions (repulsion and/or attraction) will be when the sample contacts other charged materials.

In particles, zeta potential is measured in solution-state using Electrophoretic Light Scattering (ELS). ELS is a variant methodology of Dynamic Light Scattering (DLS) and is likewise used to measure the speeds of solute particles. Unlike standard DLS, ELS evaluates particle kinetics in response to an oscillating electric field. The field induces electrophoretic movement that yields a slight frequency shift in the scattering laser beam. A collection of specialized detectors measures the magnitude and frequency of these shifts against a reference laser beam, and the resulting outputs are correlated to particle mobility and zeta potential.

In solid (macroscopic) samples, instruments instead measure Streaming Potential to interpolate zeta potential. In this technique, a solid, electrochemically active material is mounted to form a capillary channel. Then, a solution of electrolytic ions is passed through the channel under the influence of a controlled pressure gradient. As they flow, the ions induce electrophoretic effects in the slipping plane of the sample surface, causing charge carriers in this layer to rearrange. The system measures the resulting change in electrical potential as a function of electrolyte strength and uses this data to calculate the zeta potential of the sample.

Base Pricing List
No item selected Add to Quote List
Techniques
Pricing Starts At
Action
+
Zeta Potential
$300 / Sample
+
Zeta Potential: Colloidal Dispersion
$350 / Sample
+
Zeta Potential: Solid Surface (pH Range)
$900 / Sample
+
Zeta Potential: Solid Surface (single pH)
$350 / Sample

Strengths
  • ELS zeta potential is highly sensitive, with ~ 100x the detection threshold of streaming potential measurement for macroscopic solids
  • Rapid and straightforward data collection
  • Numerous sample cells available to customize method for diverse sample types
Limitations
  • Accurate Zeta Potential measurement in solid samples requires exact dimensions for the sample and capillary channel cross section
  • Zeta potential is only present when a material contacts a liquid
Sample Requirements
  • For Solid Samples:
    • Minimum Particle Size (Powders): 25 μm
    • Sample Cells Available: Cylindrical, Adjustable-Gap, Clamping
    • Irregular sample geometries and nonplanar samples are not well suited for this measurement
  • For Liquid Samples:
    • Required Sample Volume: 2 mL
    • Particle Size Range: 3.8 nm to 100 μm
    • Maximum Sample Concentration: 70 % w/v
Instruments Used for
Anton Paar SURPASS 3

Anton Paar SURPASS 3

  • Streaming Potential Voltage: ± 2000 mV
  • Streaming Current: ± 2 mA
  • Cell Resistance: 5 Ω to 20 MΩ
  • pH Scan Range: 2 to 12
  • Temperature Range: 20 °C to 40 °C
Anton Paar Litesizer 500

Anton Paar Litesizer 500

  • Potential Range: ± 1000 mV
  • Particle Size Range: 3.8 nm to 100 μm
  • Temperature Range: 0 °C to 90 °C
Example Outputs
<p>Zeta potential distribution of carbon-black dispersed in toluene.</p>
<h6>From: Anton Paar</h6>

Zeta potential distribution of carbon-black dispersed in toluene.

From: Anton Paar
<p>Surface zeta potential of SiN wafers after cleaning by hydrofluoric acid, displayed as a function of pH.</p>
<h6>From: Anton Paar</h6>

Surface zeta potential of SiN wafers after cleaning by hydrofluoric acid, displayed as a function of pH.

From: Anton Paar
Additional Resources

No resources available at this time.

Similar Techniques

comparison link sent successfully
please use valid email address
You need to have at least 2 techniques to compare
You can select maximum 5 techniques
Covalent uses cookies to improve your browsing experience and to help you access the most relevant information and services efficiently. To learn more, view our
Decline
I Accept Cookies
techniques selected
Select at least 2 techniques to compare Compare techniques