|00:00:44||Zeta Potential & Isoelectric Point Characterization|
|00:03:00||Targeted Drug Delivery Systems|
|00:04:24||Cosmetics / Personal Care|
|00:05:25||Paints & Industrial Coatings|
|00:07:04||Part Two: Measurement, Double Layer, Resulting Zeta Potential|
|00:07:24||What is Zeta Potential?|
|00:08:53||DLVO Theory, 1940’s|
|00:13:21||Electrophoretic Light Scattering|
|00:16:36||Electrophoretic Light Scattering(Zeta Potential)|
|00:18:10||Measurement Cells (for use under 70C)|
|00:20:22||Diffusion barrier technique|
|00:23:54||Electro-Osmosis and ELS|
|00:26:33||Eliminating Electroosmosis:Aqueous/Non-Aq Dip Cell|
|00:27:31||Mobility vs. Cell Position 0.5Hz & 50Hz|
|00:28:53||Mobility Results vs. Frequency|
|00:30:01||Mixed Mode Measurement (M3)|
|00:31:20||Phase Plot From General Purpose|
|00:35:41||MAINTAINING COLLOIDAL STABILITY|
|00:36:06||Maintaining Dispersion Stability|
|00:36:11||ELECTROSTATICS:Origins of Surface Charge in Aqueous Media|
|00:41:09||Predicting Dispersion Stability|
|00:41:31||Zeta Potential and pH|
|00:42:35||Effect of pH on Particle Charge|
|00:42:40||Zeta Potential and Conductivity|
|00:42:57||Non Specific Ion Adsorption|
|00:43:42||Specific Ion Adsorption|
|00:43:47||Part Three: Isoelectric Points|
|00:46:59||Origin of Charge in Clays|
|00:48:10||Surface Charge - Neutral Conditions (pH7)|
|00:49:12||Example Isoelectric Points of Oxides|
|00:50:06||Part Four: Formulation- Sunscreens/Sun Lotions|
|00:50:06||Photochemistry and Photobiology of the Skin|
|00:50:54||Sunscreen Agents: Two Kinds|
|00:51:57||Physical (Particulate) Sunscreen Materials|
|00:52:40||Microfine Metal Oxide UVR Attenuation Spectra|
|00:53:04||Uncoated Titanium Dioxide & Zinc Oxide|
|00:54:13||Surface Treated Titanium Dioxide & Zinc Oxide|
|00:55:48||Particle Size Growth ZnO & TiO2 (pH 7.0)|
|00:58:56||Thank you for your attentionAny questions?|
Zeta potential is a function of both the particle surface and the dispersant medium. It is an important predictor of electric or charge stabilization and can also be used to identify the adsorption of non-ionic or steric layers. In short, zeta potential provides key information about the interfacial behavior of multicomponent formulated products.
Particles acquire a surface charge when exposed to a polar medium like water. There are many origins of this surface charge depending upon the nature of the particle and it’s surrounding medium. Typically, materials in water are negatively charged but there are some materials that are positively charged. An isoelectric point (IEP), is the pH at which a molecule or material carries the average nett charge of zero. The IEP can affect the solubility of a molecule at a given pH. Materials typically have minimum stability or minimal solubility in water or salt solutions at the IEP and often coagulate or precipitate out of solution at this pH. The IEP also indicates the acidity and alkalinity of the material. Again, the zeta potential is affected by both the particulate, or dispersed phase, as well as the dispersion medium. Zeta potential is important in evaluating product consistency, product quality and final product performance.
In this presentation, we will discuss zeta potential measurements, zeta potential theory, charging mechanisms that affect surface interfacial behavior and isoelectric point determination.
Dr Ana Morfesis is Applications Specialtist for our Nanometrics product group. She joined Malvern in 1999 and works with us in conjunction with the Carnegie Mellon University Lab. Ana has a PhD in Physical Chemistry from the University of Massachusetts. Her area of research has been colloid and surface chemistry since the early 1980's.
Pour en savoir plus
Learn about zeta potential and how it can help you to formulate products.
Who should attend?
Formulation scientists working in pharmaceuticals, drug delivery, surfactants, personal care, industrial coatings, paper products, ceramics and academic researchers studying interfacial and surface behavior of two phase suspensions and complex fluids