Surface tension is the expression of the mutual attraction between molecules on the surface of liquid, and is an important parameter in the properties of liquid. The platinum ring surface tensiometer, also known as the du Nouy ring, suspended ring surface tensiometer, and unlooped surface tensiometer, is a commonly used method for measuring surface tension. This paper will introduce the principle of platinum ring surface tensiometer, the points for attention in application and purchase.

Principle and measurement method
The platinum ring method is based on a series of steps: First, the platinum ring is gently dipped into the liquid to be measured. Then, the platinum ring is slowly lifted upward, causing the liquid level to drop, forming a liquid column, and eventually the platinum ring is separated from the liquid. At this time, the highest value of separation between the platinum ring and the liquid is recorded, which is formed in the state of contact between the platinum ring and the liquid but not completely separated. This maximum value is the result of the surface tension measurement. Tips: The accuracy of this maximum value will be affected by the viscosity of the liquid, so the viscosity of the liquid has a certain impact on the accuracy of the measurement results.

Application principle and precautions of platinum ring surface tensiometer

Application precautions
Although the platinum ring surface tensiometer is an effective measurement method in many cases, it can be problematic in some specific cases. In particular, when applied to measurements of samples or surfactants with viscosity, the following problems arise:

Viscosity calculation effects: When measuring a sample with viscosity, viscosity can have an impact on the measurement results. This is because the platinum ring method fails to take viscosity into account, making it impossible to accurately measure surface tension.

Single time point measurement: the platinum ring method can only measure the surface tension value of a single time point, and can not realize the surface tension value test that changes with time. For applications where liquid properties change over time, this may not be applicable.

Application principle and precautions of platinum ring surface tensiometer

Purchase points: In the purchase of platinum ring surface tensiometer, there are several key points to note:

Surface tension principle: Understand the surface tension measurement principle used by the instrument to ensure that it is suitable for the desired application scenario.

Scope of application: Confirm whether the instrument is suitable for measuring samples or surfactants with viscosity, and select the appropriate instrument according to the actual needs.

Time change testing: If necessary, choose an instrument that can achieve time change measurement to meet specific experimental requirements.

Platinum ring design: pay attention to the design of platinum rings, especially whether its thickness design meets the requirements. Make sure the platinum ring is of good quality to obtain accurate measurement results.

Sum up
Platinum ring surface tensiometer is a commonly used surface tension measurement method. Its principle is simple and it performs well in many application scenarios. However, when measuring samples or surfactants with viscosity, one needs to be aware of their limitations. In the purchase of instruments, choose the appropriate instrument according to the actual needs, and pay attention to the design of the platinum ring to ensure that accurate and reliable measurement results are obtained.