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Option - CMC
As the concentration of many surfactant solutions is increased, a point is reached beyond which the surface tension shows essentially no further decrease, thus giving a sharp change in the slope of a surface tension vs. concentration curve. This point is referred to as the critical micelle concentration, CMC.
The CMC is an important characteristic of a surfactant. Before reaching the CMC, the surface tension changes strongly with the concentration of the surfactant. After reaching the CMC, the surface tensions remains relatively constant or changes with a lower slope.
The automatic CMC option for the drop shape tensiometer, Tracker™ is a quick and efficient way of finding and determining the CMC by scanning a surfactant solution over a defined concentration range, while measuring the surface tension of the liquid-air interface.
Principle
The CMC can be determined by carrying out surface tension measurements on a series of different surfactant concentrations.
For the CMC measurement of TrackerTM, a set of concentration data is setup in the measurement configuration. Distilled water is first put into a measuring cuvette containing a stirred solution. A rising bubble is formed by the Tracker and the image is analyzed to get the surface tension.
The surfactant solution then is injected into the cuvette. The new surface tension is calculated by Tracker software. The surfactant concentration is again increased and this procedure is repeated a number of time to get the surface tension at different concentrations. |
CMC option - Cuvette holder
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During the CMC measurement, the Tracker software displays the surface tension versus the concentration. After the whole CMC measurement, the CMC point is fitted.
The automatic CMC option allows up to four solutions of different dosing concentration to be dosed into the measuring cuvette of the Tracker™. The dosing volume is carefully controlled by the dosing syringe.
The dosing volume and concentration is completely controlled by a software algorithm that calculates the concentration steps in order to optimize the precision of the CMC determination. |
Tracker software - CMC measurement
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