STABILIZATION OF FATTY-ACID MONOLAYER AND MULTILAYER BY SIMULTANEOUS POLYELECTROLYTE COMPLEXATION AND SALT FORMATION WITH CADMIUM IONS

The complexation of highly ordered fatty acid monolayers with polyelec trolytes is expected to yield well-ordered Langmuir films suitable for the formation of Langmuir-Blodgett multilayers with improved long-ter m stability. Studies of the surface pressure-area isotherms and of the surface potential kinetics yield detailed information regarding the i nfluence of these polymeric counterions on the monolayer properties. T he injection of bivalent metal salts into the subphase after the compl exation was used to improve the order and stability of the mono- and m ultilayers. The corresponding Langmuir-Blodgett Alms were investigated by means of X-ray reflectivity measurements and scanning force micros copy. The polyion complex multilayers show a strongly increased mechan ical stability compared with films of fatty acid salts formed with biv alent metal ions. These structures are expected to be suitable as ultr athin separation layer for gas separation or ultrafiltration membranes . (C) 1997 Elsevier Science S.A.