Techniques based on transient interfacial disturbances

The whole theoretical treatment of the derivation of interfacial response ftmctions was discussed recently by Miller et al. (1991). It was shown by Loglio et al. (1991a, b, 1994) that exchange of matter functions derived for harmonic disturbances can be applied to transient ones. 

The derivation of Ay(t) for surfactant mixtures and the consideration of specific peculiarities of 1/1 interfaces was described by Miller et al. (1991). For a surfactant mixture, consisting of r compounds, the functions Ay(t) results from the exchange of matter relations Eqs (6.19) and 

The surface tension response fimction Ay(t) of relaxations at the liquid/liquid interface has exactly the same form as the one at the liquid/air interface, except the characteristic frequency is defined in a different way, taking into account the peculiarity of solubility of the surfactant in both adjacent phases (cf. Eq. (6.22)). 

As mentioned above, beside the diffusion-controlled models, others exist to describe the adsorption kinetics and exchange of matter. De Feijter et al. (1987) have developed a relation taking into consideration simultaneous adsorption of proteins and surfactants at an interface. As a special case a relation results which describes the equilibrium state of adsorption of polymer molecules at a liquid interface. 

The isotherm Eq. (6.32) results as equilibrium state of the following kinetic relation 

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