Pigmenttestung und Stabilitätsprüfung von Dispersionen
Auftragstestung und anwendungsorientierte Entwicklung
Dispersions
Measurement of Electrokinetic-Sonic-Amplitude ESA
Characterisation of suspensions, dispersions, colloides and paste-like formulations up to high concetrations. The simultaneous measurement of zeta-potential, pH-value, specific conductivity and temperature is possible during stirring. This ESA-technology enables extensive possibilities in the field of dispersion research and recipture development, particularly due to the titration of specific agents which for example either react with the particle's surface or don't.
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ESA measurement for your applications
The ESA method is an electro acoustic measuring technique for characterising the charge stability of particles in dispersion.
An oscillating voltage, generated by an AC source, is applied to a suspension, dispersion, or emulsion.
Charged particles in dispersion vibrate with the frequency of an applied electric field. One or more frequencies can be applied. Sound waves are generated by the particle oscillation at these frequencies.
The amplitude of these sound waves gives the Electrokinetic-Sonic-Amplitude (ESA). The ESA signal is proportional to the dynamic mobility of the particle, which in turn is proportional to the zeta potential of the particles in dispersion. In order to use the ESA method, a certain density difference between the dispersion medium and the particle is required. For evaluable signals, a density difference of at least 0.1 g/cm3 is required. The measurements can be carried out with dispersions in aqueous, alcoholic, organic solutions and paste-like formulations.
Electrostatic Stabillity ESA
The ESA method of our laboratory is state of the art for electro acoustic methods and has been developed for a whole range of different applications.
During the technical process, dispersions are often found to be highly concentrated, muddy, coloured, tempered, or electro-statically affected by additive formulations. Sedimentation is often inhibited by powerful agitators in the large scale treatment containers. All these process conditions can be included in our ESA stability analysis. The results of the analysed highly concentrated samples correlate directly with the electro kinetic properties of the dispersed particle in both the raw material and the final product.
We carry out dispersion research and give answer to important questions:
How dispersions are stabilized and how is the influence on the dispersion properties ?
In wich way process can affected by parameter of formulation.
ESA-analysis for quality contol, product and process development
Fully functional transport, storage and processing behavior can be ensured by the analysis of electrostatic dispersion stability. An exact analysis of dispersion stability is a requirement during reception development.
The surface chemistry of a dispersion can be controlled during the measurement of Electrokinetic Sonic Amplitude (ESA) by regulating the pH value e.g. for avoiding flocculation of dispersion. This means: the zeta potential of the dispersion should not be zero or close to this figure.
Zeta potential is a dimension of the effective surface charge of particles and the interaction between the particles with ions in solution and particles among each other. Characterising the absolute surface charge (in an aqueous dispersion) of the particles (negative or positive in the unit [mV]) gives a decisive parameter for an ultimate application of the product.
The zeta potential depends on the kind of solvent used, the nature and amount of the ions in solution (specific conductivity), and the pH value. It is also the main factor when determining the stability of the whole dispersion.