Fig. 9. Schematic representation of the different equilibria involving the surfactant molecules taking place in a polymer–surfactant solution: a) free surfactant molecule in solution–sur- factant adsorbed at the air–water interface; b) free surfactant molecule in solution–surfactant in free micelle; c) free surfactant molecule in solution–surfactant in the polymer complex; d) surfactant in free micelle–surfactant in the polymer complex; e) surfactant in free micelle–surfactant adsorbed at the air–water interface; f) surfactant in the polymer complex — surfactant adsorbed at the air–water interface.