2.6. Additional Measurements
2.6.1. pH Measurements
pH measurements were made by dipping into the emulsion the pH sensor of a WTW pH 535 microprocessor.
2.6.2. Surface/Interface Tension Measurements
The surface tension measurements were taken with the Wilhelmy plate technique using a KSV Sigma 70 tensiometer. The platinum plate was partially immersed into the oil layer, where it remained to fixed position during the course of the experiment. Thus, the surface tension decreased as a function of time. When the surface tension was stabilized then the experiment was stopped. For the interfacial tension measurement Ring Du Nouy method was used. A ring from platinum was going down and immersed into the water phase. Then carefully the oily phase was being placed from the top of the water one. The ring was pulling up until the lamella from the inter- face breaks off. At this point the measured force gives interfacial tension value. This method has an easy han- dling, big accuracy and does not depend on wetting con- tact angle. All measurements were made at 25°C ± 0.1°C.