Nanoengineering of Metallic Solutions Through Silicone ConstructsBhanu P. S. Chauhan,a* Rajesh Sardar,a Umar Latif,a Moni Chauhan,b and William J. Lamoreauxc
In this review, we present the summary of preliminary results of our recent investigations on the synthesis, stabilization and characterization of functional metallic nanoclusters and their assembly in various physicochemical environments. These investigations are based on the “meatball-spaghetti” strategy, devised in our laboratory, we are investigating silicon based nanoreactors (spaghetti) for generation and stabilization of nano-objects (meatballs). In the first part, a one pot, highly efficient reduction of silver acetate to stable nanosized silver particles is described. This new strategy involves utilization of poly(methylhydro)siloxane as reducing and stabilizing agent and permits routine formation of stable 2 nm size silver particles in common organic solvents at room temperature. The role of physicochemical and morphological property profile of polysiloxanes in nucleation, growth and stabilization processes is also discussed. The ligand exchange studies of nanosilver pools in grafting the surface properties of silver particles is also presented. In the second part, cyclic and cubic siloxanes templates are used for the generation of miceller network in presence of polyethylene glycol units. The miceller network is used for the room temperature reduction of Ag and Pd metal salts to metal colloids, in organic solvents, by “polyol like process”. The cases are presented, which demonstrate that network not only acts as a reducing agent, but as a stabilizer as well. Electron microscopy studies show non-aggregated metal nanoparticles with narrow size distributions, which are evenly trapped in micelles.
Key words: Nanoclusters, polysiloxane, collagen, nanoreactors and cyclic templates