Effects of adsorption on detergency phenomena: II

Knowledge of adsorption of active agents onto different interfaces is fundamental to their technical application in the washing and cleaning process. Particularly important is their influence on interactions in multicomponent systems. By the formation of mixed adsorption layers consisting of at least 2 surfactants, an enhancement of adsorption is attained as compared with the adsorption isotherms of individual components. Parallel to this, the washing effect also increases. Water-soluble complexing agents are adsorbed specifically onto polar surfaces, particularly onto such surfaces that contain calcium ions. Their affinity to such surfaces is significantly greater than those of surfactants which are mainly adsorbed onto hydrophobic interfaces. Due to the complex composition of soil, both components complement each other. In addition to their ion exchange capacity for bivalent ions, zeolites have a certain ability to adsorb molecularly dispersed soil components as well as colloidal particles. Hence, they have a special effect as antiredeposition agents. Polymeric antiredeposition agents act by formation of adsorption layers on pigments and fibers. Only such compounds that cannot be displaced completely from interfaces by competing adsorption with surfactants show positive antiredeposition effects.