Synthesis of Silver Nanoparticles by Precipitation in Bicontinuous Microemulsions

Abstract

Silver nanoparticles precipitation was carried out at70∘Cin bicontinuous microemulsions stabilized with a mixture of surfactants sodium bis (2-ethylhexyl) sulfosuccinate/sodium dodecyl sulfate (2/1, w/w) containing an aqueous solution of 0.5 M silver nitrate and toluene as organic phase. Various concentrations of aqueous solution of sodium borohydride (precipitating agent) and their dosing times on microemulsions were studied. Regardless of dosing time, higher and medium concentrations of precipitating agent promoted the formation of worm-like nanostructures, while the lowest concentration allowed to obtain a mixture of isolated silver nanoparticles (mean diameter≈3 nm) and worm-like nanostructures. Experimental yields much higher than those typical in precipitation of silver nanoparticles in reverse microemulsions were obtained. An explanation for formation of worm-like nanostructures based on the development of local zones inside the microemulsions channels with high particle concentrations was proposed.

Modification of Electrical Properties of Silver Nanoparticle

“…There is apparently no other peaks, except the silver crystal peaks. All of the peaks shown in Figure 2 can readily fit in a model of FCC structures, as also reported previously [37] for various PEG [23], for the different surfactant, and [38] for urea, PVP, and dextrose. Further refined to the lattice parameter gives rise to a = 4.0876 Å.…”

“…Among these methods are ball milling method [22], precipitation [23], polyol method [24], and several other methods to produce silver nanoparticle [3,[25][26][27][28].…”

New Trends on the Synthesis of Inorganic Nanoparticles Using Microemulsions as Confined Reaction Media

“…Furthermore, the yield of the reactions was as high as 1.16 g of product per 100 grams of microemulsion, which is rather high compared to what can be obtained in most w/o microemulsion systems (0.05 -0.2 grams per 100 g microemulsion). The same research group reported recently the synthesis of silver nanoparticles by the same approach (Reyes et al, 2010;Sosa et al, 2010), by using a microemulsion system based on AOT/SDS as the surfactant system and toluene as the oil. Depending on the surfactant: oil ratio, the authors found the formation of only globular nanoparticles or a mixture of interconnected, worm-like structures plus globular nanoparticles.…”

High-Yield Synthesis of Zinc Oxide Nanoparticles from Bicontinuous Microemulsions

“…In reverse microemulsion precipitation, the hydrolysis reactions take place inside the water-microemulsion droplets suspended in a hydrophobic medium; however, this technique has the drawback that the productivity of nanoparticles is low. Some authors have employed bicontinuous microemulsions rather than w/o microemulsions because the ratio of water-to-oil is larger, which increases the productivity of metal oxide nanoparticles, keeping the typical size of nanoparticles obtained in reverse microemulsions [22,[27][28][29].…”