Preparation of silver spheres by aggregation of nanosize subunits

Abstract

Dispersed uniform spherical silver particles were prepared in the absence of a protective colloid by rapidly mixing concentrated isoascorbic acid and silver-polyamine complex solutions. By varying the nature of the amine, temperature, concentration of reactants, silver/amine molar ratio, and the nature of the silver salt, it was possible to tailor the size of the resulting metallic particles in a wide range (80 nm to 1.3 m). The silver spheres were formed by aggregation of nanosize subunits, the presence of which was detected by both electron microscopy and x-ray diffraction. Due to its simplicity, high metal concentration, and the absence of polymeric dispersants, the described method represents an advantageous route to manufacture cost-effectively dispersed uniform silver particles for electronic applications. II. EXPERIMENTAL A. Reagents and solutionsEthylenediamine (EDA), diethylenetriamine (DETA), triethylenetetraamine (TETA), tetraethylenepentamine

Computational model for the formation of uniform silver spheres by aggregation of nanosize precursors

“…This experimental system was described and characterized in detail recently. 28 The system has commercial relevance as a straightforward way to produce uniform dispersed silver particles that are useful in the production of silver conductive structures in the electronics industry. Several methods, including photoreduction, spray pyrolysis, and precipitation in homogeneous solutions or reverse micelles, are available for the preparation of silver particles.…”

“…28 yields spherical silver particles of a narrow size distribution, with an average diameter ranging from 80 nm to 1.3 µm. From the applications point of view, this method is favorable, because, in contrast to most precipitation protocols, it generates dispersed silver spheres in concentrated systems in the absence of a dispersing agent.…”

“…In Sec. II, we summarize the experimental procedure and results reported recently 28 for the production of uniform silver spheres. In Sec.…”

Peptide‐Coated Silver Nanoparticles: Synthesis, Surface Chemistry, and pH‐Triggered, Reversible Assembly into Particle Assemblies

“…[5,6] Electromagnetic radiation, [7][8][9][10][11] dimethylformamide (DMF), [12] ascorbate, [13][14][15] and citrate [16][17][18][19] are common reducing agents for silver salts. Ascorbate and citrate have become popular for their "green" connotation, but they also lead to uniform nanoparticles, [20] including nanorods, [21] core-shell structures, [22,23] and polyamine- [24] and polysulfonate-stabilized [14,25] nanoparticles. Current research focuses on factors that control the shape, size, and size distribution of the particles by using ascorbate.…”

Preparation of counterion stabilized concentrated silver sols

“…While thermolysis [7], pyrolysis [8], and electrolysis [9] have been often used to produce finely dispersed silver, the reduction in homogeneous solutions remains the most effective method for tailoring particle size, shape, and uniformity [10][11][12]. The versatility of this approach derives from the ability to rigorously control the experimental conditions for a broad range of solvents [13], reductants [14], complexing agents [15], and dispersants [16].…”