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SDT Spinning Drop Tensiometer

KRÜSS

SDT Spinning Drop Tensiometer is ideal for the measurement of interfacial tension over a wide range using image analysis for optimising emulsions and micro emulsions accurately.
Manufacturer KRUSS
Product Series KRUSS Tensiometer
Measurement principle Interfacial tension (IFT) calculated by image analysis
Application Surface Tension – Contact Angle
Sample type Emulsions and micro emulsions used in applications like lubrication, cosmetics or enhanced oil recovery
Temperature control -10 to 120 °C
Range (interfacial tension) 10-6 to 2000 mN/m (resolution 10-6 mN/m)
Sample stage tilting ±20°

The KRUSS SDT Spinning Drop Tensiometer measures interfacial and surface tension with a high degree of accuracy and within wide measuring range, ideal for the development of mini- and micro-emulsions and surfactants. Extremely low interfacial tension can be measured accurately for a range of applications such as enhanced oil recovery and food or pharmaceutical/ cosmetic formulations.

Controlled rotation and image evaluation

Interfacial and surface tension measurements are carried out by analysing video images of a drop or bubble within a fluid, inside a rotating capillary. This method involves a horizontally positioned capillary filled with a bulk phase and a lighter drop phase, set into rotation. The centrifugal force elongates the drop, and its diameter or curvature is correlated with the interfacial tension. Using the rotational speed, the interfacial tension is accurately determined based on the deformation of the drop. A high-resolution camera and precision motor, paired with the intelligent image evaluation algorithms of the ADVANCE software, are used to capture and analyse these measurements.

Innovations for speedy sample preparation

Quick and easy to use with patented sample handling functionality and equipped with flexible heating options as well as a drop-tracking camera, the SDT elevates the spinning drop technique enabling advanced studies. An accurate infrared sensor measures the temperature contactless and reproduces the thermal conditions directly at the place of measurement.

Software that is workflow-orientated
The ADVANCE software focuses on simple automation with intuitive operation. SDT is completely software-controlled and uses prepared and easily modifiable templates. In addition to the Young-Laplace method, the SDT also analyses the drop shape using the traditional Vonnegut method. The SDT is packed with innovations to improve emulsion development.

Resources

  • Measurement of interfacial tension in a wide range down to 10-6 mN/m
  • Analysis using the drop diameter according to Vonnegut
  • Analysis using the drop shape curvature according to Young-Laplace
  • Long-term measurement for analysing surfactant dynamics
  • Temperature-dependent analyses
  • Development of emulsions
  • Enhanced oil recovery (EOR)
  • Bioavailability of drugs
  • Surfactant research
  • Adsorption properties at phase boundaries

How does the SDT measure interfacial tension?

The SDT measures interfacial tension by analysing the diameter or curvature of a drop of a lighter liquid phase placed inside a heavier liquid phase within a rotating capillary. As the capillary spins, centrifugal effects elongate the drop — the greater the elongation relative to the rotation speed, the lower the interfacial tension. The ADVANCE software performs image analysis on the drop shape in real time using a high-resolution camera and a precision motor with excellent speed constancy.

What interfacial tension measurement range does the SDT cover?

The SDT measures interfacial tension across a range of 10 to the power of -6 to 2,000 mN/m with a resolution of 10 to the power of -6 mN/m — a span of six decades. This wide range makes it suitable for both conventional liquid-liquid systems with high interfacial tension and ultra-low interfacial tension systems such as microemulsions used in enhanced oil recovery, where values approach zero.

What analysis methods does the SDT use to evaluate drop shape?

The SDT uses two complementary methods. The Vonnegut method evaluates the diameter of an elongated drop and is the traditional approach for spinning drop measurements. The Young-Laplace method evaluates the full curvature of the drop shape and is more robust — it extends the measurable range to higher interfacial tensions, effectively broadening the overall measurement bandwidth beyond what the Vonnegut method alone can cover.

How does the SDT control and measure sample temperature during measurement?

The SDT includes an integrated electric heater that rapidly reaches target temperatures and maintains exact constancy throughout the measurement. Temperature is recorded using an infrared sensor that measures contactlessly in close proximity to the drop itself — directly at the measurement location rather than at the instrument housing. The operating temperature range is -10 to 120 degrees C.

What are the primary applications of the SDT?

The SDT is suited for the development and quality control of emulsions and microemulsions used in lubrication, cosmetics, food science, and pharmaceuticals. It is widely used in enhanced oil recovery (EOR) surfactant flooding research, where ultra-low interfacial tension between oil and water phases is critical. Additional applications include drug bioavailability analysis, surfactant research, and studying adsorption behaviour at phase boundaries.

How does the SDT’s sample handling support throughput?

The SDT features a unique, patented procedure for quick capillary drop insertion that vastly increases sample throughput compared to conventional spinning drop instruments. The sample stage can be tilted by +/-20 degrees to assist with sample positioning. The ADVANCE software supports performing up to 20 consecutive measurements while displaying all results simultaneously, enabling time-dependent and temperature-dependent result series without manual restarts.

Can I have a demonstration of the SDT?

Yes, if a system is available. Contact us for a booking. We can arrange a personalised demo and test your samples within our lab facility in Sydney. Onsite free trials are also available. Contact us to get started.

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