Metal Nano Networks by Potential‐Controlled In Situ Assembling of Gold/Silver Nanoparticles

Abstract

Non‐spherical Au/Ag nanoparticles can be generated by chemical reduction of silver ions in the presence of preformed gold nanoparticles. The process of particle formation can be controlled by concentrations of ligands and reducing agent. The formation of ellipsoidal, nanorod‐ and peanut‐shaped nanoparticles as well as of more complex fractal nanoassemblies can be explained by changes in particle surface state, electrochemical potential formation and particle‐internal self‐polarization effects. It is possible to create highly fractal nanoassemblies with sizes between the mid‐nanometer and the lower micrometer range. The assemblies are marked by high optical absorption and complex nano‐networks of very high surface‐to‐volume ratios and a granular base structure.

In Situ Assembly of Gold Nanoparticles in the Presence of Poly-DADMAC Resulting in Hierarchical and Highly Fractal Nanostructures

“…This could be the reason for the preferential edge-and corner-oriented growth of flat gold nanoprisms induced by an attractive Coulomb interaction between the positively polarized particle corners and the negatively charged tetrachloroaurate. The formation of nonspherical, star-like and special-shaped crystalline gold nanoparticles [31][32][33] depends on the empirically optimized composition of reaction solutions and is known to be related to symmetry breaking during nanoparticle formation [47]. It is assumed that the effect of the poly-DADMAC is mainly related to the electrostatic effect of macromolecules adsorbing onto the surface of growing nanoparticles.…”

“…Besides the factors that determine the crystallographic structures and shape of the gold nanoparticles (polynuclear spheres, nanocubes, triangular or hexagonal nanoprisms and nanorods, for example), electrostatic interactions between the particles play a crucial role in the formation of structures and assemblies of different shapes and sizes [23][24][25][26][27][28]. These interactions account for the colloidal stability and the formation of nonspherical nanoparticles [29] such as star-like nanoaggregates [30]; networks formed by in situ interaction of the particles during the growth process [31]; and formation of ellipsoidal, dumbbell and astragal-like shapes of polymer-containing nanoparticles [32]. The synthesis of nanoparticle structures in the presence of macromolecules also depends on these electrostatic interactions.…”

A Comprehensive Review of the Efficacy, Mechanisms and Future Prospects of Nano Iron Supplementation in Piglets

“…Hemoglobin as a dietary source of haeme, which is a highly bioavailable organic iron, to effectively counteract the onset of iron deficiency anemia in piglets [48]. Iron nano particles (IONPs) have emerged as a potent instrument in various biomedical [49] and environmental applications [50]. The literature extensively reports that IONPs have the potential to function as drugs and/or gene carriers, in addition to serving as contrast agents or hyperthermal mediators in anticancer therapy [51].…”

Metal Nanoparticles as Free-Floating Electrodes

“…An electrostatic model was proposed for the formation of networks of Au/Ag nanoparticles during the deposition of silver on preformed spherical gold nanoparticles [34]. It describes the preferred bonding of spherical particles on the poles of nanorods due to the induced polarization by the electrostatic interaction of the charged metal nanoparticles.…”