• Drop Shape Analyzer – DSA30R

    Drop Shape Analyzer – DSA30R

  • Analysis of oscillating pendant drop in a liquid surrounding phase

    Analysis of oscillating pendant drop in a liquid surrounding phase

  • Oscillating Drop Module – ODM of the DSA30R

    Oscillating Drop Module – ODM of the DSA30R

Drop Shape Analyzer – DSA30R

Analyses in interfacial rheology – time-saving and reproducible

Emulsions and foams are constantly in motion during production or transport. The interfaces of droplets or bubbles are stretched during these processes. How such deformations impact on the stability of food and bodycare products or influence the yield in tertiary crude oil production depends on how the surface tension or interfacial tension (SFT/IFT) responds to the stretching. Interfacial rheology measurements with the Drop Shape Analyzer – DSA30R provide the key to answering this question.

Elasticity and viscosity analysis in a wide dynamic range

The measuring principle involves evaluating video images of drops or gas bubbles at a dosing needle to measure the surface or interfacial tension. The interface size is sinusoidally changed during this process. The SFT/IFT is measured as a function of the surface change and is also sinusoidal in the case of samples containing surfactants.

The dosing unit’s extremely precise piezo drive enables exact sine waves in a frequency spectrum of 0.001 to 20 Hz, so the measurements cover a very wide dynamic range.

The elastic modulus E’ and the viscous modulus E’’ result from the evaluation. E’ goes hand in hand with the change to the surfactant’s surface concentration due to stretching and compression;  E’’ reflects the change in SFT/IFT with respect to time due to diffusion and interfacial adsorption of the dissolved surfactant. Both quantities are related to the mechanical and temporal stability of foams and emulsions.

Quick, simple and exactly repeatable measurements

Many innovations around the DSA30R turn formerly complex interfacial rheological analytics into an easy-to-follow method with quick sample changing. The liquid is simply added to a standard glass syringe, which is inserted in just a few steps, then fully automatically and magnetically coupled to the dosing feed.

Cleaning is completely unproblematic thanks to the technical separation between the liquid reservoir and the oscillation drive. The same is true for the filling process with zero air bubbles, which prevents undesirable oscillation damping and thus guarantees reliable results.

The entire measurement process, from drop generation and oscillation to the results output, is fully automatic. This is ensured with easy-to-create ADVANCE software automation programs. The measuring conditions are optimally repeatable thanks to the fully software-controlled measurement using fixable parameters.

Measurements at a controlled temperature

To determine the influence of temperature, or to make investigations of high-viscosity systems easier, the syringe is embedded in a temperature-controlled sleeve for measurements between -10 and 70 °C, whereby the temperature of the surrounding phase can also be controlled. The ADVANCE software documents the temperature curve throughout the entire measurement. Also, the start of certain processes such as the beginning of oscillation can be automatically linked to the target temperature being reached. In this way, reproducible conditions without user interventions are guaranteed.

Tasks and applications

  • Emulsions and foams for food or body care
  • Flooding mixtures and foam in enhanced oil recovery
  • Demulsifiers
  • Defoamers and antifoamers
  • Surfactant research

Measurement options

  • Measurement of interfacial rheological parameters such as the elastic modulus E’ and viscous modulus E’’
  • Analysis of oscillating pendant or rising drops in a gaseous and liquid surrounding phase
  • Measurements on oscillating gas bubbles
  • Static surface and interfacial tension
  • Measurement at temperatures ranging from -10 to 70 °C

Contact Angle Rheology

  • DSA30R  |  interfacial rheology

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Foam behavior
Food & Beverages
Surface rheology
Oil & Gas