The kinetics of synthesis and mechanism of coagulation of gold nanoparticles in Triton N-42 reverse micelles

Булавченко, А. И.; Арымбаева, А. Т.; Татарчук, В. В.

doi:10.1134/s003602440805018x

Cited by 19 publications

(10 citation statements)

References 6 publications

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“…The reaction proceeds by forming complexes of gold ions with a reductant onto the surface of the gold particle. 41,42 Because cyclodextrin can form inclusion complexes with anions, cyclodextrin might bind with an intermediate AuCl 2…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Gold Nanoparticles by Tetrachloroaurate Reduction With Cyclodextrins

Pestovsky¹,

Martı́nez-Antonio²

2018

Quim. Nova

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One-step synthesis of gold nanoparticles functionalized with α-, βand γ-cyclodextrins was carried out using a synthetic method of direct tetrachloroaurate reduction in alkaline solutions. The two experimental conditions studied were direct heating and microwave irradiation. This is the first publication comparing the characteristics of gold nanoparticles produced using three cyclodextrins under different conditions. The resulting nanoparticles were characterized by absorbance spectra, FTIR spectra, dynamic light scattering data and transmission electron microscopy images. The reducing ability of cyclodextrins increased in the following order: β-cyclodextrin < α-cyclodextrin < γ-cyclodextrin. Therefore, γ-cyclodextrin was the most active reductant and the only cyclodextrin that was able to reduce tetrachloroaurate at room temperature. In this case, nanoparticles were observed only after 4 days of storage. The nanoparticle size was dependent on the cyclodextrin type and correlated with the difference in the reducing ability. Using microwave irradiation, most of nanoparticles were found to be free nanoparticles. Using direct heating, aggregates formed due to the high ionic strength of the solution after prolonged boiling. Therefore, nanoparticles synthesized by direct heating were less stable during storage than those synthesized by microwave irradiation.

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Section: Resultsmentioning

confidence: 99%

Synthesis of Gold Nanoparticles by Tetrachloroaurate Reduction With Cyclodextrins

Pestovsky¹,

Martı́nez-Antonio²

2018

Quim. Nova

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“…Growth can occur by both an autocatalytic process on the surface of gold nuclei (surface reduction) and by reducing radicals 54. 63 The Au 0 species formed combine to form gold nuclei, Au n 54. 62 A limited number of gold nuclei (Au n ) are formed during the nucleation process and a maximum number of nuclei is reached under specific experimental conditions 62.…”

Section: Resultsmentioning

confidence: 99%

Sonochemical Synthesis of Gold Nanoparticles by Using High Intensity Focused Ultrasound

Yusof

Ashokkumar

2015

ChemPhysChem

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The sonochemical synthesis of gold nanoparticles (GNPs) with different shapes and size distributions by using high-intensity focused ultrasound (HIFU) operating at 463 kHz is reported. GNP formation proceeds through the reduction of Au(3+) to Au(0) by radicals generated by acoustic cavitation. TEM images reveal that GNPs show irregular shapes at 30 W, are primarily icosahedral at 50 W and form a significant amount of nanorods at 70 W. The size of GNPs decreases with increasing acoustic power with a narrower size distribution. Sonochemiluminescence images help in the understanding of the effect of HIFU in controlling the size and shapes of GNPs. The number of radicals that form and the mechanical forces that are generated control the shape and size of the GNPs. UV/Vis spectra and TEM images are used to propose a possible mechanism for the observed effects. The results presented demonstrate, for the first time, that the HIFU system can be used to synthesise size- and shape-controlled metal nanoparticles.

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“…Spontaneous separation of salts from microemulsions was not observed during synthesis. Noticeably, the opposite situation is more frequently observed in reduction of metals: it is quite problematic to obtain stable microemulsions with nanoparticles, because coagulation frequently starts during synthesis [25]. The situation with water soluble salts is more com plex: in microemulsions, we have not salt nanoparti cles; rather, we have their solutions.…”

Section: Results and Discussion Preparation And Characterization Of Pmentioning

confidence: 99%

Microemulstion synthesis of powders of water-soluble energy-saturated salts

Булавченко

Демидова

Podlipskaya

et al. 2012

Russ. J. Inorg. Chem.

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769Microemulsion (micellar) synthesis is a popular method and is widely used for preparing nanoparticles of metals [1], oxides [2], and sparingly soluble salts [3,4]. The advantages of this method include: (1) the ease of synthesis; (2) a narrow particle size distribution function of the product; (3) a feasibility of preparing particles of complex composition, multilayered, hybrid, and other types of particles [5]; and (4) a good knowledge of the micellar and microemulsion struc ture. Unfortunately, there only few studies directed to the preparation of nanoparticles of water soluble salts by the microemulsion method. For example, Co(NO 3 ) 2 , CaCl 2 , Na 2 HPO 4 , and Cu(NO 3 ) 2 nanopar ticles have been prepared in a solid phase concentrate in an AOT matrix (sodium di(2 ethylhexyl)sulfosucci nate) via distilling off the solvent (heptane) and water [6,7].Meanwhile, studies of microemulsion synthesis as applied to prepare powders and liquid hydrophobic concentrates of nanoparticles of water soluble energy intensive salts seem to be very promising for both sci ence and application. For example, reverse emulsions of supersaturated ammonium nitrate solutions [8,9] in diesel fuel have almost substituted for TNT con taining industrial explosives [10-13].Our goal here was to study the possibility of prepar ing powders of water soluble salts in reverse micro emulsions of oxyethylated surfactant Tergitol NP 4. EXPERIMENTALReagents The micelle forming surfactant used was oxyethy lated nonylphenol with an average oxyethylation number of four, namely, Tergitol NP 4 (from Dow Chemical). A micellar solution contained 0.25 mol/L Tergitol NP 4 in n decane. The organic solvents used were pure grade n decane and N,N dimethylforma mide (DMF) and high purity grade heptane and ace tone. The initial reagents used were concentrated nitric acid (high purity grade, 16.2 mol/L), concentrated aqueous ammonia (high purity grade, 10.8 mol/L), KOH, and NaBH 4 (both of pure grade), NH 4 NO 3 (pure for analysis grade), and KNO 3 (chemically pure grade). Structural Study of Microemulsions and PowdersThe limiting solubilization capacity V s /V o (the vol ume ratio of an aqueous solubilizate solution to a sol ubilizate containing micellar solution) of a micro emulsion system with respect to aqueous solutions of reagents and salts was determined by serial injections of small volumes of the aqueous phase. The cloud point was detected visually and spectrophotometri cally by an abrupt increase in the absorbance of the solution. Measurements were carried out on a Shi madzu 1700 spectrophotometer using quartz cells (l = 1 cm); the reference solution was a "dry" micellar solution.Microemulsions with initial reagents were structur ally studied by photon correlation spectroscopy and Abstract-The feasibility of preparing energy saturated salts (NH 4 NO 3 , KNO 3 , and NaBH 4 ) in powders with various particle sizes in microemulsion systems based on oxyethylated surfactant Tergitol NP 4 has been demonstrated. Powders were isolated by destroying microemulsio...

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The kinetics of synthesis and mechanism of coagulation of gold nanoparticles in Triton N-42 reverse micelles

Cited by 19 publications

References 6 publications

Synthesis of Gold Nanoparticles by Tetrachloroaurate Reduction With Cyclodextrins

Synthesis of Gold Nanoparticles by Tetrachloroaurate Reduction With Cyclodextrins

Sonochemical Synthesis of Gold Nanoparticles by Using High Intensity Focused Ultrasound

Microemulstion synthesis of powders of water-soluble energy-saturated salts

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