Concentrated synthesis of metal nanoparticles in water

Abstract

The synthesis of a range of metal nanoparticles (Ag, Au, Pd, Pt) in water through reduction from the acid 10 soluble salt at abnormally high concentrations (>1 mol/L) is demonstrated using a comb polymer of methoxypoly(ethylene glycol) acrylate and maleic anhydride (PEG-MA) as the particle stabiliser during particle formation. The results show that at high concentrations in water, the general growth mechanism in these systems is through aggregation of nuclei of an approximate diameter of 0.6 nm. Aggregation resulted in formation of single crystals up to a particle diameter of approximately 5 nm but thereafter, 15 further aggregation resulted in polygonal twinned particles. Continued aggregation caused agglomerate particles to be formed at larger sizes (>30 nm). Stabiliser adsorption was found to be critical to size control whereby the aggregation process was interrupted, preventing further growth. A case of the synthesis of Ag nanoparticles with a mean size of 8nm at concentrations of up to 2.5 mol/L is elaborated.

A First Wide‐Open LDH Structure Hosting InP/ZnS QDs: A New Route Toward Efficient and Photostable Red‐Emitting Phosphor

“…For TA‐LDH, no changes are noticed neither on XRD nor on SAXS data after fabricating the QD‐TA‐LDH indicating that the QDs fail to be incorporated into the interlamellar space (Figure S7a,b, Supporting Information). In the case of the PEG 1000 , home‐made synthesized (ESI – Section S1, Supporting Information), presenting both the length (8.3 nm) [ 34 ] and the α/ω functionalization comparable to ones of the bola (Figure S8a, Supporting Information), the syntheses by coprecipitation or by the polyol method fail to produce the desired hybrids. As presented on the XRD patterns (Figure S8b,c, Supporting Information), the spacers are counter‐anion of the starting salts, nitrates and acetates for coprecipitation and polyol route, respectively.…”

A Gallium-Based Magnetocaloric Liquid Metal Ferrofluid

“…Similar nanoparticle loading in aqueous suspensions can only be achieved when elaborate surface modification and stabilization strategies are employed. 28 The finding highlights that low temperature liquid metals should be considered for nanomaterial synthesis alongside conventional molecular and ionic solvents. Magnetic hysteresis loops (MHLs) were measured at temperatures ranging from 300 K to 5 K, using magnetic field strengths up to 2 T, with a ramping rate of 100 Oe s −1 .…”

Stable Coloured Micrometric Films from Highly Concentrated Nano-Silver Sols: The Role of the Stabilizing Agents

“…Remarkably, as regards the last compound, several polymers have been investigated so far. Anderson et al [ 10 , 12 ] reported the synthesis of highly concentrated (>1 M) yellow spherical Ag NPs by exploiting a methoxypoly(ethylene glycol) acrylate and maleic anhydride (PEG-MA) blend. Other studies have revealed that the binding ability of water-soluble polymers, such as polyvinylpyrrolidone (PVP) and polyvinyl alcohol (PVA), to the silver surface represents the tool to control the nucleation, growth and shape of the final NPs [ 13 , 14 , 15 ].…”

“…In particular, yellow concentrated sols (up to ca. 2 M [ 12 ]) have already been largely described; whereas an optimized synthesis method for the other concentrated (200 μM) Ag colors has not been reported so far, due to the great instability of these sols. Furthermore, herein, the next step forward is the successful deposition of these concentrated sols onto a crown-treated polyethylene terephthalate (PET) support, in order to develop transparent colored micrometric films, preserving the initial color of Ag sols and limiting particle sintering during the solvent evaporation.…”