Force Tensiometers

Sigma force tensiometers are widely used in research, quality control and process control for the determination of:

• Surface tension
• Interfacial tension
• Critical micelle concentration
• Powder wettability
• Dynamic contact angle
• Sedimentation wettability
• Surface free energy
• Absorption
• Adhesion force
• Cleanliness
• Surface heterogeneity
• Density

Force tensiometry is a powerful and accurate technique to measure static surface and interfacial tension of liquids. These direct measurements allow determination of a number of material and surface properties, such as dynamic contact angle, surface free energy, critical micelle concentration and wettability. This information can be used to determine adhesion, absorption, adsorption, cleanliness, surface heterogeneity, density, spreading, porosity, powder or sedimentation wettability, material solubility, biocompatibility and lubricity of solid surfaces, to name but a few. Force tensiometry has become the method of choice for many industrial standards related to characterisation of liquids. It is also the most widely used technique for measuring critical micelle concentration (CMC) of surfactants. In addition, it is the only method to determine the absorption and contact angle of a packed powder or of fibre beds using the Washburn method. The wetting of textiles and individual fibres can also be studied with Sigma force tensiometers.

Measurement principle
When a liquid touches the surface of a solid, the liquid tends to be drawn up in a meniscus. The force exerted by the meniscus is measured and analysed to determine surface tension. Using high surface free energy probes such as a platinum Du Noüy ring or Wilhelmy plate allow precise measurement of these forces. All Sigma force tensiometers measure surface and interfacial tension using plates or push and pull modes by ring. Correction calculations for rings are made using models from Huh and Mason (Harkins and Jordan, Zuidema & Waters and others also available).

The Instruments:
Sigma force tensiometers are precision instruments with unparallelled ease of use. They all feature high precision balances and mechanics, intuitive software and open design for easy access to the different parts of the instrument.

Sigma 700

Sigma 700 is a state-of-the-art force tensiometer, providing highly accurate measurements of static surface and interfacial tension, dynamic contact angles and fully automatic CMC determination. Full computer control and a high level of automation make it possible to carry out long measurements without operator intervention during the test, saving time and freeing the user to concentrate on other tasks. Special attention has been paid to the ergonomic and user-friendly design. Sigma 700 is outstandingly versatile, making it suitable for research and development, industrial quality control, routine measurements and even educational use. Accessory modules for dispensers, temperature or pH control can be easily mounted into the measuring unit. In addition, special probes are available for density, sedimentation and tensiometry measurements as well as holders for powder, fibre and plate studies. Software modules are independent and can be acquired separately, giving you the flexibility to customise the instrument to your needs. Modules are available for the following measurements: surface and interfacial tension, dynamic contact angle, CMC, density, powder wettability and sedimentation. Two dispensers can be used simultaneously for CMC measurements, allowing a full CMC curve to be obtained in one measurement. Because of its wide weight range and auto-calibrating microbalance, the Sigma 700 is well suited for dynamic contact angle measurements of large and heavy solid and powder samples.

Sigma 701

Sigma 701 is a state-of-the-art force tensiometer, providing highly accurate measurements of static surface and interfacial tension, dynamic contact angles and fully automatic CMC determination. Full computer control and a high level of automation make it possible to carry out long measurements without operator intervention during the test, saving time and freeing the user to concentrate on other tasks. Special attention has been paid to the ergonomic and user-friendly design. Sigma 701 is outstandingly versatile, making it suitable for research and development, industrial quality control, routine measurements and even educational use. Accessory modules for dispensers, temperature or pH control can be easily mounted into the measuring unit. In addition, special probes are available for density, sedimentation and tensiometry measurements as well as holders for powder, fibre and plate studies. Software modules are independent and can be acquired separately, giving you the flexibility to customise the instrument to your needs. Modules are available for the following measurements: surface and interfacial tension, dynamic contact angle, CMC, density, powder wettability and sedimentation. Two dispensers can be used simultaneously for CMC measurements, allowing a full CMC curve to be obtained in one measurement. The Sigma 701 is a multipurpose force tensiometer but equipped with a different microbalance optimised for a different range of applications. Sigma 701 can measure in a narrower weight range but with improved sensitivity, optimised for fibre measurements.

Sigma 702

Sigma 702 is a standalone force tensiometer offering high resolution and precision for surface and interfacial tension measurements, as well as non-automatic CMC determination. Results are displayed on a large integrated digital screen. Precise temperature control can be ensured by the integrated water-jacketed vessel holder. The open design and convenient control keyboard operations make Sigma 702 an extremely easy to use instrument. The instrument can be connected to an external PC for additional data storage and simple reporting. Data collection software is provided with the instrument.

Sigma 702ET

Sigma 702ET is a standalone force tensiometer offering high resolution and precision for surface and interfacial tension measurements, as well as non-automatic CMC determination. Results are displayed on a large integrated digital screen. Precise temperature control can be ensured by the integrated water-jacketed vessel holder. The open design and convenient control keyboard operations make the Sigma 702ET an extremely easy to use instrument.  Specially designed for oil-water interfacial tension measurements in line with ASTM and IEC standards. Software specifically designed for oil-water measurements is provided. The instrument can be connected to an external PC for additional data storage and simple reporting. Data collection software is included.

Sigma 703D

Simple to use and robust the Sigma 703D is a standalone digital tensiometer that will give you accurate measurements of both surface and interfacial tension of liquids by using the DuNouy ring or Wilhelmy plate methods.  The instrument can be used to perform non-automatic CMC measurements.  The measurements are displayed in real-time on the large digital screen that is integrated into the instrument, this data can easily be transferred to a computer using the data collection software.  Ideal for fast and reliable stand-alone operations under manual control, the Sigma 703D is the right choice.

Typical Applications

Sigma 703D is a force tensiometer for determination of:

• Surface tension
• Interfacial tension
• Critical micelle concentration
• Density

Available Measurements

• Static surface tension
• Static interfacial tension
• Non-automatic critical micelle concentration

Balance Specifications