SDS-PVP Clusters As Soft Template In The Preparation Of Ni-containing Nanoparticles

Surfactant and macromolecule can self-assembly into soft clusters, and the interaction between them has been studied a lot. There is also interaction between metal ions and clusters, and the clusters' structure, morphology and size can be adjusted. So that it is possible to prepare metal or metal containing alloy by using clusters as soft template.In this paper, the interaction between metal ions and sodium dodecyl sulfate(SDS)- polypirrolidone(PVP) cluster was studied, and the cluster was used as soft template to prepare nickel-containing nanoparticle.1. The interaction between metal ions and SDS-PVP clusterThe interaction between metal ions and SDS-PVP cluster was studied via surface tension method, steady-state fluorescence probe technique, laser light scattering, ultra-filtration and UV-Vis spectroscopy. Surface tension results show that the existence of metal ions will not destroy the formation of SDS bound-micelle. When the SDS concentration increases to the first critical concentration (c1), SDS aggregate on the PVP chain and form bound-micelle. The increase of metal ions'concentration favors the formation of bound-micelle, and make surface tension decrease further. In the meantime, c1 decreases while the second critical concentration (c2) increases with the increase concentration of metal ions, the clusterization boundary of SDS-PVP cluster extend. Bivalent metal ions have stronger ability than monovalent metal ions in decreasing the surface tension of SDS-PVP solution, the ability of them to make surface tension decrease is Li+ < Na+ < K+< Ni2+≈Cd2+≈Cu2+. Ultra-filtration results show that nickel ions can bind with the head group of SDS and thus associate with SDS-PVP cluster. When the nickel ions associated with clusters are reduced to form nanoparticles, the SDS molecules and the nearby PVP molecules can in situ adsorb and prevent the overgrowth of them. Using pyrene as probe and benzophenone as quencher in steady-state fluorescence technique, the aggregation number of bound-micelle (Nb) of metal ions-SDS-PVP complex was measured. According to the experiment result, Nb increases with the addition of SDS. When nickel ions concentration is high, the addition of SDS into the solution makes Nb increase slower while surface tension does not decrease or less, it means that more SDS bound-micelle form on PVP chains. The results of microenvironment polarity show that the microenvironment polarity of bound-micelle decreases with the addition of SDS, implying that the arrangement of surfactant in bound-micelle become compacter. On the other hand, the microenvironment polarity of bound-micelle decreases with the additon of nickel ions. Therefore, the amount of SDS bound-micelles can be adjust through changing SDS and nickel ions'concentraion, the size of SDS bound-micelles and the distance between each SDS...