Control of Colloid Growth and Size Distribution by AdsorptionSilver Nanoparticles and Adsorbed Anisate

Abstract

We study the formation of silver colloids and the effect of an additive on their growth by measuring the kinetics of silver reduction in the presence of anisic acid, combined with transmission electron microscopy. The kinetics show an initial fast reduction of 1−3% of the total silver present in the solution, then a plateau region with hardly any reduction going on, and finally a region of accelerated growth and aggregation. The results are interpreted quantitatively in terms of the adsorption of the additives on the silver clusters at the early stages of the reaction and a slow-down of their subsequent growth. This is an example for the use of additives to achieve a control over the size distribution of colloidsdetermining the average size of the particles and the width of the distribution.

Physical Characteristics of Stabilized Silver Nanoparticles Formed Using a New Thermal-Decomposition Method

“…Furthermore, the HRTEM shows that the distribution is significantly sharper than those found using most other methods, even without using special distribution-narrowing methods [9,10]. The method of Burshtain et al [11] also gives a fairly mono-disperse distribution.…”

“…Judging by the frequency of multiple twins, the nucleation probably more closely resembled that in the gas-evaporation method [13] than that in the metal colloid-in-aqueous-solution method. However, the size and monodispersity of the particles is nearly that of the Ag nanoparticles of Burshtain et al [11] that were grown by the colloid method. They gave convincing evidence that the surface coating nearly halted growth at 8 nm.…”

Novel synthesis of well-dispersed crystalline SnO2 nanoparticles by water-in-oil microemulsion-assisted hydrothermal process

“…First, the polar reactants of urea and tin salt are confined in the nanoscale water pools, which ensures the relatively higher local reactant concentration. The resulting higher reactant concentration makes the nucleation easier, and fast nucleation tends to produce smaller and more numerous particles [25]. Second, the monodispersity of the reverse micelles leads to homogeneous nucleation and narrows down the size distribution.…”

Magnesium hydroxide nanoparticles synthesized in water-in-oil microemulsions

“…First, the reactants of Mg 2+ ions and aqueous ammonia were confined in the nanometer-sized water pools, which ensured a relatively higher local reactant concentration. The resultant higher reactant concentration made the nucleation easier, and fast nucleation tended to form smaller and more numerous crystallites [27]. Second, all the stages of nucleation, growth, and crystallization of nanoparticles were carried out in the confined nanoscaled water pools of the w/o microemulsion.…”