Sonication induced amorphisation in Ag nanowires

It has long been conjectured that pure-element face-centred cubic (fcc) metals can be transformed into a glassy state by deformation at ultra-high strain rates. However, when an impact force is applied at the nanoscale, deformation-induced melting prevents observations of fcc metal amorphisation. Here we propose a sonication treatment of Ag nanowires (fcc) and confirmed amorphisation induced by high strain rates at bent areas of the Ag nanowires. Owing to the mismatch of the deformation modes between the core and the surface, we observed a diameter related increase of the ductility of Ag nanowires under deformation at ultra-high strain rates generated by sonication. The sonication-prepared amorphous Ag was stable at room temperature. Amorphous Ag at the bent areas was highly reactive and was readily recrystallized under light illumination or vulcanised. Our study verifies the occurrence of high strain rate induced amorphisation in pure fcc MGs and provides a powerful tool for mechanical studies on metal nanomaterials under extremely high strain rates and forces.

A Facile Route for Synthesis of Octyl Amine Capped Silver Nanoparticle

This paper presents a simple and convenient procedure for the preparation of octyl amine capped silver nanoparticles. AgNO 3 has been reduced by octyl amine with benzene or toluene as solvent at 100°C to produce silver nanoparticles. Octyl amine plays its role both as reducing and capping agent and thus provides the advantage of avoiding the use of extra stabilizing agent. Time dependent formation mechanism of silver nanoparticle has been investigated. Thermo gravimetric analysis (TGA) shows weight change due to loss of capping agent. The reaction can easily be monitored from variation of color with time. The method is easy and reproducible. Very low concentration (1 mM) of metal ion is used. The particles synthesized were characterized by UV-Visible, FTIR, TGA, TEM and X-ray diffraction studies.

The size control of silver nanocrystals with different polyols and its application to low-reflection coating materials

The size of silver nanocrystals in polyol synthesis can be simply controlled by tuning the viscosity of the reaction medium such as ethylene glycol, 1,2-propanediol, 1,4-butanediol and 1,5-pentanediol. We found that a higher viscose medium (1,5-pentanediol) led to monodispersed smaller particles thanks to the slow addition of silver atoms into the nuclei. Size-controlled silver nanocrystals of 30 nm were obtained in a viscosity controlled medium of 1,5-pentanediol to synthesize a low refractive index filler by coating with silica and subsequent etching of the silver core. The coated low-reflection layer from the hollow silica nanoparticles on polyethylene terephthalate (PET) film can greatly reduce the reflection of the PET film from 10% to 2% over the entire visible region.

Silver nanoparticles capped by oleylamine: formation, growth, and self-organization

Nearly monodisperse silver nanoparticles have been prepared in a simple oleylamine-liquid paraffin system. Intensive study has found that the formation process of silver nanoparticles could be divided into three stages: growth, incubation, and Ostwald ripening stages. Ultraviolet-visible spectroscopy, transmission electron microscopy (TEM), and high-resolution TEM have all demonstrated the occurrence of Ostwald ripening, which could result in better control over the size and size distribution of silver nanoparticles. SAXS (small-angle X-ray scattering) results show that the as-obtained silver nanoparticles can self-assemble into ordered arrays. The possible reduction mechanism of silver ions by oleylamine is related to the Ag+-mediated conversion of primary amines to nitriles.

Preparation and Study of Polyacryamide-Stabilized Silver Nanoparticles through a One-Pot Process

A one-pot route was illustrated to synthesize stable well-dispersed silver colloids stabilized by polyacrylamide on a large scale. Reduction of silver ions and polymerization of acrylamide occurred almost simultaneously in the absence of a commonly used reducing agent and initiator. A possible mechanism for the formation of silver nanoparticles with bimodal size distribution was proposed. The structure and composition of the obtained nanoparticles were characterized carefully. Furthermore, light scattering simulation and UV-vis absorption studies confirmed that the obtained colloids were the mixture of Ag and Ag2O nanoparticles. The presence of silver oxide layers on the nanoparticle surface should be responsible for the broadening of the surface plasmon band of silver nanoparticles. Ag2O layers could be added or removed from Ag nanoparticle surfaces by the addition of HNO3, HAc, or NaCl solution to the as-obtained silver colloids.