Inverted micelles and microemulsions in the ternary system water/aerosol-OT/isooctane as studied by photon correlation spectroscopy

Zulauf, M.; Eicke, Hans‐Friedrich

doi:10.1021/j100467a011

Cited by 859 publications

(608 citation statements)

References 3 publications

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“…Diffusion of uncharged DTPA molecules is slower, and adsorption at the initial stage is due only to Van der Waals attraction. However, with time, DTPA molecules start to form strong, preferably donor-acceptor bonds with AuNPs due to sulfur atoms possessing high affinity to chalcophilic gold [33], and displace AOT from the surface layer. Thus, AOT provides intermediate stabilization of AuNPs.…”

Section: Resultsmentioning

confidence: 99%

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Di-(2-ethylhexyl) dithiophosphoric acid surface protected gold nanoparticles: micellar synthesis, stabilization, isolation, and properties

et al. 2011

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Gold nanoparticles (AuNPs) were synthesized in the organic solution by means of the reduction of HAuCl 4 by hydrazine in reverse micelles of oxyethylated surfactant Triton N-42, with decane as the dispersion medium. To isolate the powder of particles, the micelles were destroyed with chloroform in the presence of di-(2-ethylhexyl) dithiophosphoric acid as a surface protecting agent. According to the results of several experiments, the yield is within the limits of 90-98%, calculated for gold. The obtained preparations are dark blue hydrophobic powders containing aggregated but not agglomerated gold nanoparticles, as well as microcrystals (∼0.08-0.2 μm) of NaCl. The powders get re-dispersed in weakly polar organic solvents with the formation of colloidal solutions. The shape of the nanoparticles is spherical. Their nuclei are gold single crystals with a narrow size distribution; their diameter (d Au ) is about two times as large as the diameter of the aqueous nucleus (d c ) of initial micelles: d Au =7.7±

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Section: Resultsmentioning

confidence: 99%

“…Crystalline HAuCl 4 ⋅3H 2 O was synthesized from metal Au according to the conventional procedure [33].…”

Section: Methodsmentioning

confidence: 99%

Di-(2-ethylhexyl) dithiophosphoric acid surface protected gold nanoparticles: micellar synthesis, stabilization, isolation, and properties

et al. 2011

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“…To ensure that the organic layer is confined to the surface, we chose AOT, sodium bis(2-ethylhexyl) sulfosuccinate (Figure 1), a wellknown surfactant with a strong propensity for forming inverted micelles in condensed phase. [37][38][39] Figure 2 shows an experimental schematic for generating nanoparticles and monitoring their hygroscopic growth. Nanoparticles containing NaCl and AOT were generated with a homebuilt electrospray aerosol source.…”

Section: Introductionmentioning

confidence: 99%

Hygroscopic Growth and Deliquescence of NaCl Nanoparticles Coated with Surfactant AOT

et al. 2009

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Aerosolized nanoparticles of NaCl coated with variable amounts of surfactant AOT were generated by electrospraying AOT/NaCl aqueous solutions, followed by neutralizing and drying the resulting particles. A tandem differential mobility analyzer was used to select a narrow size distribution of particles with mobility equivalent diameters below 20 nm and monitor their hygroscopic growth as a function of relative humidity. Effects of the particle size and relative amount of surfactant on the hygroscopic growth of NaCl were studied. For pure NaCl nanoparticles, the deliquescence relative humidity (DRH) increased as the particle size was decreased, in full agreement with previous measurements. Below the DRH the NaCl nanoparticles had an equivalent of one-four monolayers of water adsorbed on the surface. The addition of a sub-monolayer AOT coating reduced the DRH and suppressed the hygroscopic growth of the NaCl core. At AOT coverage levels exceeding one monolayer, a clear deliquescence transition was no longer discernible. The Zdanovskii-StokesRobinson (ZSR) model failed to predict the observed growth factors of mixed AOT/NaCl nanoparticles reflecting a large contribution of the interfacial interactions between NaCl and AOT to the total free energy of the particles. There were indications that AOT/NaCl nanoparticles prepared by the electrospray aerosol source were enhanced in the relative mass fraction of AOT in comparison with the solution from which they were electrosprayed.

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“…Variations in this parameter are accompanied by changes in the size of the inner water cavity of reversed micelles [30,31]. Maximal enzyme catalytic activity in reversed micelles is observed at a particular degree of surfactant hydration, namely when the size of the inner cavity corresponds to that of the entrapped protein (general regularities of the phenomenon are discussed in [17]).…”

Section: Resultsmentioning

confidence: 99%

Formation and properties of dimeric recombinant horseradish peroxidase in a system of reversed micelles

Gazaryan

Klyachko

Dulkis

et al. 1997

Biochemical Journal

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Wild-type recombinant horseradish peroxidase purified and refolded from Escherichia coli inclusion bodies has been studied in the system of bis(2-ethylhexyl)sulphosuccinate sodium salt (Aerosol OT)-reversed micelles in octane. In contrast with native horseradish peroxidase the wild-type recombinant enzyme forms dimeric structures as judged by sedimentation analysis. Peroxidase substrates affect the equilibrium between monomeric and dimeric enzyme forms. The dependence of the catalytic activity of recombinant peroxidase on the degree of hydration of the surfactant exhibits two maxima with pyrogallol, o-phenylene- diamine, guaiacol and o-dianisidine, with different ratios of activities for the first and second maxima. The differences in activities of monomeric and dimeric forms of the recombinant horseradish peroxidase provide evidence for active-site screening in dimeric forms. This has been used to model a dimeric structure of recombinant horseradish peroxidase with the screened entrance to the active site. In the model structure obtained, three of eight glycosylation sites were screened. This might explain the absence of dimeric structures in native enzyme peroxidase. The system of reversed micelles provides, for the first time, evidence for the formation of dimeric structures by recombinant plant peroxidase with an altered substrate specificity compared with the native enzyme. Thus one can assume that haem-containing peroxidases in general are able to form dimeric structures.

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Inverted micelles and microemulsions in the ternary system water/aerosol-OT/isooctane as studied by photon correlation spectroscopy

Cited by 859 publications

References 3 publications

Di-(2-ethylhexyl) dithiophosphoric acid surface protected gold nanoparticles: micellar synthesis, stabilization, isolation, and properties

Di-(2-ethylhexyl) dithiophosphoric acid surface protected gold nanoparticles: micellar synthesis, stabilization, isolation, and properties

Hygroscopic Growth and Deliquescence of NaCl Nanoparticles Coated with Surfactant AOT

Formation and properties of dimeric recombinant horseradish peroxidase in a system of reversed micelles

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