Advantages of Wilhelmy Plate method

The DyneMaster series measures surface tension using the Wilhelmy Plate method (standard) or the du Nouy Ring method (optional). These techniques differ not only in the detection components but also in the action used. The Wilhelmy Plate method keeps the plate in contact with the liquid, while the du Nouy Ring method requires removing the ring from the liquid.

The Wilhelmy Plate method has the following advantages compared with the du Nouy Ring method:

• Variations of surface tension over time can be measured.
• Surfactant solution generally decreases surface tension with time due to the accumulation of molecules at the surface. The Wilhelmy Plate can measure these variations continually, since the plate does not need to be removed. (Removal causes a corresponding decrease in the surfactant concentration.)
• Compatible with medium to high viscosity materials.
• Such liquid materials tend to cling to the detection component, which prevents a clean break of the membrane and creates a stress unrelated to surface tension.
• Fragility of detection component
• In general, the platinum plate of the Wilhelmy is sturdy and reasonably resistant to deformation. The du Nouy ring is fragile and susceptible to deformation during regular handling and cleansing. Also, installation of the plate is straightforward, compared with the delicate ring.

Pendant Drop method

This measurement technique for surface/interface tension is possible with the Dropmaster series contact angle meter using an optional module.

This method has the following features:

• The same hardware can be used with a contact angle meter.
• It is better suited to measure higher viscous liquids or the lower interfacial tension of two liquids.
• It can measure small samples of liquid. Even a 1mL sample allows several measurements.

> Pendant Drop Method