COMPLEXES OF POLYELECTROLYTE GELS WITH OPPOSITELY CHARGED SURFACTANTS- INTERACTION WITH METAL-IONS AND METAL NANOPARTICLE FORMATION

The interaction of polyelectrolyte gel/oppositely charged surfactant c omplexes with AgNO3 and H2PtCl6 was investigated. Three kinds of gel/s urfactant complexes were studied: a complex of the anionic gel of poly (methacrylic acid) with the cationic surfactant cetylpyridinium chlori de and complexes of the cationic gel of poly(diallyldimethylammonium c hloride) with two anionic surfactants: sodium dodecyl sulfate and sodi um dodecylbenzenesulfonate. After reduction of metal compounds by hydr azine-hydrate, sodium borohydride, or UV-irradiation, Pt and Ag metal particles embedded in the body of the hydrogel were formed. The degree of metal ion exchange was higher for the oppositely charged metal ion and the polyelectrolyte gel; i.e., Ag+ is strongly absorbed by the co mplex poly(methacrylic acid)/cationic surfactant, while PtCl62- ions a re mainly consumed by the complex of poly(diallyldimethylammonium chlo ride) gel with anionic surfactants. Small-angle X-ray scattering data indicated different structural changes in the gel for the complex of a n anionic gel with cationic surfactant and for complexes of cationic g el with anionic surfactants. The incorporation of the metal ions in th e body of the hydrogel and the growth of metal nanoparticles was found to lead to the loss of order provided by surfactant aggregates if the distance between charged groups in the polyelectrolyte does not provi de a strong hydrophobic interaction between surfactant molecules.