Impact of the bulk aggregation on the adsorption of oppositely charged polyelectrolyte-surfactant mixtures onto solid surfaces.

The understanding of the deposition of oppositely charged polyelectrolytes-surfactant mixtures onto solid surfaces presents a high interest in current days due to the recognized impact of the obtained layers on different industrial sectors and the performance of several consumer products (e.g. formulations of shampoos and hair conditioners). This results from the broad range of structures and properties that can present the mixed layers, which in most of the cases mirror the association process occurring between the polyelectrolyte chains and the oppositely charged surfactants in the bulk. Therefore, the understanding of the adsorption processes and characteristics of the adsorbed layers can be only attained from a careful examination of the self-assembly processes occurring in the solution. This review aims to contribute to the understanding of the interaction of polyelectrolyte-surfactant mixtures with solid surfaces, which is probably one of the most underexplored aspects of these type of systems. For this purpose, a comprehensive discussion on the correlations between the aggregates formed in the solutions and the deposition of the obtained complexes upon such association onto solid surfaces will be presented. This makes it necessary to take a closer look to the most important forces driving such processes.