ORDERED NONSTOICHIOMETRIC POLYMER GEL-SURFACTANT COMPLEXES IN AQUEOUS-MEDIUM WITH HIGH IONIC-STRENGTH

The effect sodium chloride on the composition and structure of network polymer-surfactant complexes (NPSC) formed by slightly cross-linked n etworks of poly(diallyldimethylammonium chloride) (PDADMACL) and oppos itely charged surfactants of sodium dodecylbenzenesulfonate (SDBS) was studied. The comparison of the composition of NPSC with the data obta ined by SAXS shows that, at some content of the surfactant ions in the gel phase, highly ordered lamellar structure in NPSC is formed. In th e solution of high ionic strength and at significant excess of the sur factant molecules in the external solution, this highly ordered NPSC c an be strongly nonstoichiometric. The excess of the surfactant anions in the polyelectrolyte network first increases with the increase of th e ionic strength of the solution, reaching a maximum at c = 0.3 M NaCl , and only after that starts to decrease. The degree of spatial order in NPSC becomes more pronounced when the nonstoichiometric complexes i n the solution of high ionic strength are formed. These results are ex plained by introducing the model in which the fitting of packing of th e surfactant and polymer components in NPSC is improved by the inclusi on of extra surfactant molecules together with their counterions in th e highly ordered structure.