Measurement principle: When a solid touches the surface of a liquid, the liquid tends to be drawn up in a meniscus. The force exerted by the meniscus is measured by a microbalance using a Du Noüy ring or a Wilhelmy plate, in either push or pull mode. The microbalance reading is used to calculate surface tension using a selection of software models.
Force tensiometry is an accurate technique to measure the static surface tension and interfacial tension of liquids. These direct measurements allow the determination of dynamic contact angle, surface free energy, powder wettability, absorption, cleanliness, surface heterogeneity and density. It is also widely used for measuring critical micelle concentration of surfactants and the only method to determine the absorption and contact angle of packed powders and fiber beds.
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| Sigma 700/701 | Sigma 702/702ET | Sigma 703D |
Sigma 700/701 provide outstanding versatility with full computer control and a high level of automation. Accessory modules for dispensers, temperature and pH control can easily be mounted into the measuring unit. Special probes are available for density and wettability measurements as well as holders for fibres and plates. Software modules for specific measurements can be acquired separately. The Sigma 700 is suited for dynamic contact angle measurements of large or heavy solids and powder samples The Sigma 701 is similar but optimized for fibre measurements.
Sigma 702/702ET are open design instruments with water-jacketed holder for sample temperature control. Operation is controlled by a keyboard and results are displayed on an integrated digital screen. Available measurements are static surface tension, static interfacial tension, density and non-automatic critical micelle concentration.
Sigma 702ET is specifically designed for oil-water interfacial tension measurements to ASTM and IEC standards and includes specific oil-water measurement software.
Sigma 703D is the simplest force tensiometer with a manual stage. Results are displayed on the integrated digital screen and can be transferred to a computer. Accurate measurements of surface and interfacial tension of liquids are made by the DuNouy ring or Wilhelmy plate method. Non-automatic critical micelle concentration can also be conducted.
Click here to contact usMeasurement principle: An optical tensiometer captures the image of a liquid drop and records the drop shape as a function of time. The drop shape is determined by the surface tension of the liquid, gravity, and the density difference between the liquid and surrounding medium. The drop image is analysed with a profile fitting method in order to determine contact angle and surface tension. On a solid surface the drop contact angle also depends on the surface free energy.
Optical tensiometers or contact angle meters allow direct measurements of surface tension, interfacial tension and contact angles. This provides material properties such as wettability, absorption, surface free energy, cleanliness, surface heterogeneity and interfacial rheology. It is used for characterisation of both liquids and solids with applications ranging from surface development to controlling the purity of semiconductors.
Theta an automated optical tensiometer that measures static and dynamic contact angles, static and semi-dynamic surface/interfacial tension and surface free energy. The available drop profiles are: sessile drop, pendant drop, receding contact angle, tilting drop, advancing contact angle, captive bubble, meniscus and reverse pendant drop. The unique monochromatic cold light source minimizes sample evaporation. A high resolution camera with x6.5 zoom lens extracts drop profiles with high accuracy.
The software enables analysis of drop shapes, including the Young-Laplace equation which is able to fit the entire drop profile. Theta can function fully automated with motorised stage and dispenser enabling the programming of drop locations on the substrate.
Theta Lite the most cost-effective optical tensiometer with the same drop profiles as the Theta but with manual sample stage and liquid dispenser. It measures contact angles, surface free energy and drop volume. An extended software option increases measurements modes, data storage and data analysis capabilities.
Click here to contact usPicoliter dispenser
This additional module to the Theta Optical Tensiometer allows precision measurements with low volume drops as small as 20 pl. Picoliter dispensing is becoming increasingly important for the study of sorption phenomena in applications such as inkjet printing and printed electronics. In addition, the picoliter dispenser enables contact angle measurement of a picodrop deposited on single fiber.
Automatic XYZ sample stage
Attension offers a fully automatic sample stage with improved resolution (0.01 mm). Drop samples can be placed at desired locations to test any location of one substrate. When combined with an automated dispenser and motorized vertical liquid dispenser motion, fully software controlled measurements are possible. It is also possible to program deposition sequences along the X axis at desired intervals.
Pulsating drop module for interfacial rheology
The pulsating drop module functions by oscillating drops at frequency magnitudes of E-3 to E2 Hz, with complete control of both frequency and amplitude as well as wave shape (sine, triangle, square, etc.). This enables quick and easy interfacial New Theta modules: A picoliter dispenser, automatic XYZ- sample stage, enhanced version of Pulsating Drop Module.
Measurement principle: A capillary is immersed into the liquid sample and air is pushed through it. As the air pressure increases a bubble is gradually formed in the liquid. The pressure inside the capillary is measured. Maximum pressure is reached when the bubble is hemispherical, after which it quickly grows and leaves the capillary. The maximum pressure depends on the liquid surface tension.
Bubble tensiometers are used for the characterisation of aqueous solutions. They provide measurement of dynamic surface tension, hydrostatic pressure, effective adsorption time, bubble lifetime and dead time. They have applications in surfactants, ink jet printing, foam, emulsions, and environmental monitoring.
Bubble Tensiometer BPA-800P is able to deliver accurate dynamic surface tension and bubble lifetime measurements in less than 6 minutes. It corrects for viscosity and gravitation deformation of bubble shape and can handle short and long measuring times.
Measurements are highly automated. First the sample surface is detected, then the capillary is lowered and the temperature measured. Data is stored in integrated memory, and can be uploaded onto a computer. The instrument is portable and battery powered.
Measurement principle: Volumetric tensiometers measure surface tension by investigating the size of drops that can be made from the sample. The sample is pumped into a capillary at a constant rate. The drops that form at the end of the capillary increases in size and eventually fall. The time between drops is recorded and from this the size of the drop is obtained. The higher the surface tension the larger drops.
Volumetric tensiometers measure surface tension in order to control chemical additives in aqueous liquids. Surface tension is a function of chemical concentration in the water. Some common applications are:
The AL-20 is portable and ideal for at-line or in-lab surface tension measurements. One-button operation for measurement, calibration and cleaning. Results are obtained in 70 seconds and displayed on the large digital screen. The data is stored in memory and can be uploaded to a computer.
OL-55 is an on-line volumetric tensiometer developed for full integration to a production process. Surface tension is continuously measured which allows automatic dosage adjustments. The advanced software enables real time monitoring of surface tension, together with optional pH, temperature and conductivity.
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