Experimental results from studies of surfactants at liquid interfaces

Experimental results from studies of surfactants at liquid interfaces 

In this section a selection of experimental data is presented which demonstrate that different experimental technique partly overlap or complement each other in their range of application. Cases of partial overlap should not be interpreted as needless developments but more as additional resources to obtain information on dynamics of adsorption. On the one hand, experimental data of the same surfactant solution are performed to demonstrate the agreement between different experimental techniques. Many examples of experiments with different techniques are given in a recent paper by Miller et al. (1994b, d). 

On the other hand, results are also presented to show the experimental limitations of methods and measuring procedures. As mentioned above, the knowledge of an adsorption isotherm of a surfactant is of fundamental importance for the study of adsorption dynamics. For the surfactants discussed in this chapter, the parameters of the Frumkin isotherm are summarised in the tables of Appendix 5D. In case the interfacial interaction parameter a is zero, the Frumkin isotherm changes into a Langmuir isotherm. 

As an experimental prerequisite for studies at liquid/liquid interfaces, the two liquids have to be mutually saturated. For example, even solvents like alkanes are remarkably soluble in water and a transfer of solvent molecules across the interface would influence surfactant adsorption kinetics. The table in Appendix 5E summarises the mutual solubility of some solvents with water. 

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