In situ formation of silver nanoparticles based on dendriticlinear amphiphilic block copolymer micellar templates

Abstract

Dendritic-linear amphiphilic block copolymer, G 1 -b-PEG, was synthesized through a convergent method. The first generation benzylic dendritic polyether, G 1 -Cl, was synthesized, and benzylic dendritic polyether, G 1 -Cl, was used to react with linear monohydroxyl terminated MPEG in alkaline solution via a convergent method. The copolymer was characterized by 1 H-NMR. The amphiphilic block copolymer could self-assemble into micelles in aqueous solution, which were used as templates to prepare dispersed silver nanoparticles in water. The morphology and structure of the hybrids were characterized by transmission electron microscopy (TEM) and ultraviolet spectroscopy (UV), 1 H-NMR. An absorbance peak at 406 nm appeared after reduction in the UV spectrum. The average diameter of G 1 -B-PEG /Ag hybrid micelles was 186 nm, and the sliver nanoparticles are stable in aqueous solution due to the stabilization of the dendritic-linear micelles.

Probing Liquid/Solid Interfaces at the Molecular Level

“…535 in aqueous solution and incorporate as templates to prepare dispersed silver nanoparticles in water; that peak broadening presumably indicates the dendrimer chains adopting a solid-like structure. 557 In the case of the formation of alkanethiol-stabilized gold clusters, high-resolution NMR spectra of solutions of the clusters displayed well-defined resonances except for the methylenes nearest the gold interface, a behavior that was attributed to a combination of broadening mechanisms based on the discontinuous change in magnetic susceptibility at the metal-hydrocarbon interface and residual dipolar interactions. 558 On the basis of the line broadening seen in temperature-dependent solid-state 13 C NMR studies of those systems, a cooperative chain melting process in the alkylated metal colloids was proposed.…”

“…Changes in peak shape, broadening in particular, can be used to establish changes in the freedom of motion of specific moieties within organic chains (in surfactants, for instance), which can in turn be associated with adsorption or other type of self-assembly into solid-like structures. For instance, in one article, the broadening of specific 1 H NMR peaks was used to infer that dendritic-linear amphiphilic block copolymers self-assemble into micelles in aqueous solution and incorporate as templates to prepare dispersed silver nanoparticles in water; that peak broadening presumably indicates the dendrimer chains adopting a solid-like structure . In the case of the formation of alkanethiol-stabilized gold clusters, high-resolution NMR spectra of solutions of the clusters displayed well-defined resonances except for the methylenes nearest the gold interface, a behavior that was attributed to a combination of broadening mechanisms based on the discontinuous change in magnetic susceptibility at the metal-hydrocarbon interface and residual dipolar interactions .…”