Dynamic Methods
Surface and interfacial tensions are referred to as “dynamic” when their values, despite constant external conditions, decrease significantly with increasing age of the affected interface; in other words, they are not in thermodynamic equilibrium.
The most common methods for determining these dynamic values are the drop volume and bubble pressure methods. In the drop volume method, the dynamic surface or interfacial tension is determined from the volume of a falling drop.
In the bubble pressure method, the pressure in a small gas bubble is used to determine the dynamic surface tension. The age of the drop/bubble can be varied in both the drop volume and bubble pressure methods. This enables specific dynamic effects to be investigated. The LAUDA Tensiometers TVT 2 and MPT 2 work with very wide time ranges that overlap. Extremely precise determination of the dynamic surface tension with surface aging up to less than 1 ms is possible with the LAUDA Bubble Pressure Tensiometer MPT 2, thanks to the specially developed procedure. The Drop Volume Tensiometer TVT 2 enables measuring of interfacial tension with surface aging up to several hours.
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Dynamic Methods
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