Channel flow configuration for studying the kinetics of surfactant-polyelectrolyte binding

A novel channel flow configuration was developed and utilized for studying the poly(styrenesulfonate)-cetylpyridinium ion interaction kinetics. The surfactant solution was continuously injected into a flow of polyelectrolyte solution, and the extent of the association reaction was probed at an ion-selective detector electrode. The system was modeled within an analytical approximation, which was tested by a finite-element simulation of the full convective mass transport problem including the homogeneous complexation reaction. The results show that association kinetics can be resolved and that the initial steps of the reaction are not influenced by intermolecular interactions between the bound surfactants. The presented methodology is general, and further development should enable the study of complex cooperative kinetics of surfactant-polyelectrolyte systems.