General Approach for the Synthesis of Organic−Inorganic Hybrid Nanoparticles Mediated by Supercritical CO₂

Abstract

Abstract:We report in this paper novel chemistry that addresses the problem of surfactant solubility in supercritical CO2 for metal nanoparticle synthesis. This new approach for the preparation of organicfunctionalized inorganic nanoparticles relies on the reduction of a metal precursor in a CO2-containing insoluble polymer. Reduction of the metal with H2 leads to small nanocrystals stabilized by the polymer with a relatively small polydispersity. The functionalized metal nanoparticles are recovered as a dry powder, free of any organic solvents, which can then be resuspended in an appropriate solvent. This approach limits the number of steps for the preparation of functional nanoparticles which are ready for use. To illustrate this, we report results of the preparation of palladium and silver nanoparticles of 3-5 nm size stabilized with hyperbranched polyamines, functionalized with perfluoroalkyl, perfluorooligoether, non-fluorinated alkyl, polysiloxane, or polyethylene glycol moieties.

Hybrids of Gold Nanoparticles with Core-Shell Hyperbranched Polymers: Synthesis, Characterization, and Their High Catalytic Activity for Reduction of 4-Nitrophenol

“…In particular, the catalysis is of core interest to chemists. Beyond the enhancement of solubility and the prevention of aggregation, the organic shell can also induce selectivity in catalytic reactions and compatibility in physiological systems [21].…”

Comparative study of amphiphilic hyperbranched and linear polymer stabilized organo‐soluble gold nanoparticles as efficient recyclable catalysts in the biphasic reduction of 4‐nitrophenol

“…Dendrimers and their less‐defined hyperbranched analogs are attracting tremendous interest at present due to their specific spheroid‐like shape and multifunctionality 16, 17. Many dendrimers18–24 and hyperbranched polymers25–31 have been used to stabilize metal nanoparticles in water or organic solvents. However, comparative study of the nanoparticles stabilized by dendritic polymers, and their linear analogs was scarce 15, 32.…”

Advancements Toward the Greener Processing of Engineered Nanomaterials—Effect of Core Size on the Dispersibility and Transport of Gold Nanocrystals in Near‐Critical Solvents

“…A number of theoretical, as well as experimental, studies have been devoted to exploring the dispersibility of nanocrystals in NcFs and ScFs 18–26. Among the theoretical approaches, models such as the integral equation theory21, 22 and the total interaction theory27, 28 have been proposed to explain the interactions between these fluids and passivated nanocrystals in NcFs and ScFs.…”