Preparation of Nanoparticles in Microemulsions:  A Monte Carlo Study of the Influence of the Synthesis Variables

Abstract

Monte Carlo simulations were performed to study the formation of nanoparticles in microemulsions. The influence of the following parameters on particle size distribution (PSD) was investigated: number of reagent molecules per droplet, surfactant film flexibility, droplet size, presence or absence of autocatalysis by the product, and the fraction of bulk volume made up by droplets. It was found that autocatalyzed reactions with high reagent concentrations and low surfactant film flexibility afforded bimodal PSDs. Particle size increased with reagent concentration when this was low, but at higher reagent concentrations it depended chiefly on droplet size. The dependence of PSD on reaction time confirmed the successive occurrence of well-defined nucleation and growth processes. We have compared the simulation results with experimental data taken from different authors and carried out in our laboratory. Good agreement between both kind of results supports the conclusions of this paper.

Facile Synthesis of Stable Subnanosized Silver Clusters in Microemulsions

“…Below this size, the nuclei dissolve, because of their large Laplace pressure. Above this size, the nuclei grow continuously to reduce their surface energy by different mechanisms, such as autocatalysis or Ostwald ripening, [7] until their growth is stopped by templates or capping agents, for example.…”

Modeling of nanoparticles formation by mixing of two reactive microemulsions

“…A consequence of this phenomenon is that as the larger particles grow at ever greater rates, compared to smaller particles, multimodal distributions can arise when there is severe asymmetry between the number of particles that grows into a size range (slow) and those that grow out of it (rapid). Tojo et al (1997) also reported this in their simulation studies.…”

Continuous Tuning of Cadmium Sulfide and Zinc Sulfide Nanoparticle Size in a Water‐in‐Supercritical Carbon Dioxide Microemulsion

“…[1][2][3] Luminescence tagging and imaging, medical diagnostics, drug delivery, and nanoelectronics are some of the applications that are being developed with these nanomaterials. [4][5][6][7][8] One of the approaches utilized to synthesize these nanomaterials is the microemulsion-templated method using compressed gases as solvents.…”

“…[31] Figure 6 shows a representative excitation and emission spectra of the stabilized CdS nanoparticles obtained at two different densities of scCO 2 . A red shift of 14 nm (from 349 to 363 nm) together with an increment in the Full Width at Half Maximum (FWHM) from 48 to 63 nm, was observed in the excitation spectra when the density of the solvent decreased from 0.92 to 0.87 g mL À1 (W = 10 F-AOT concentration 10 mm).…”