DYNAMIC SURFACE-TENSION DETERMINATION USING AN AUTOMATED BUBBLE PRESSURE TENSIOMETER

A newly designed fully automated maximum bubble pressure tensiometer h as many advantages compared to known instruments developed so far The most striking feature is the possibility to determine the bubble dead time and to calculate the efficient surface age of a bubble. The state of the art of the theory for describing adsorption processes at the s urface of a growing bubble is discussed and useful approximate solutio ns are given and applied to example experiments. The temperature and v iscosity dependence of the adsorption kinetics of a model surfactant, Triton X-100, are discussed in terms of a diffusion controlled adsorpt ion model. Finally, as an example, measurements of human blood and uri ne samples ale presented in order to show the sensitivity of dynamic s urface tensions to changes in the composition of such complex liquids. Measurements of river water samples show an additional field of appli cation in water treatment control.