Aerosol® OT

The adsorption of the surfactant Aerosol OT onto Vulcan Rubber obeys the Langmuir equation [237] the plot of C/x versus C is linear. For C = 0.5 mmol/1, C/x is 100 mol/g, and the line goes essentially through the origin. Calculate the saturation adsorption in micromoles per gram. 

Cationic surfactants may be used [94] and the effect of salinity and valence of electrolyte on charged systems has been investigated [95-98]. The phospholipid lecithin can also produce microemulsions when combined with an alcohol cosolvent [99]. Microemulsions formed with a double-tailed surfactant such as Aerosol OT (AOT) do not require a cosurfactant for stability (see, for instance. Refs. 100, 101). Morphological hysteresis has been observed in the inversion process and the formation of stable mixtures of microemulsion indicated [102]. 

Dunn C M, Robinson B FI and Leng F J 1990 Photon-correlation spectroscopy applied to the size characterization of water-in-oil microemulstion systems stabilized by aerosol-OT effect of change in the counterion Spectrochim. Acta. A 46 1017... 

Zulauf M and Eicke FI 1979 Inverted micelles and microemulsions in the ternary system Fl20/aerosol-OT-isoctane as studied by photon correlation spectroscopy J. Phys. Chem. 83 480... 

H2O2 -0.9 Very extended wave (see above) sharper in presence of Aerosol OT... 

Aerosol foam Aerosol OT Aerosol packaging Aerosol paints Aerosol propellants Aerosols... 

Docusate Sodium. Aerosol OT, Colace, and Doxinate are trade names of docusate sodium [577-11-7] (dioctyl sodium sulfo succinate, sodium salt of l,4-bis(2-etliylhexyl)estet butanedioic). This white, wax-like, plastic sohd, with a characteristic odor suggestive of octyl alcohol, is usually available in the form of pellets. One gram of the sodium salt slowly dissolves in about 70 mL water. Docusate sodium is freely soluble in alcohol and glycerol, very... 

Sodium di(ethylhexyl)sulfosuccinate (Aerosol-OT) [577-11-7] M 444.6. Dissolved in MeOH and inorganic salts which ppted were filtered off. Water was added and the solution was extracted several times with hexane. The residue was evaporated to one fifth its original volume, benzene was added and azeotropic distillation was continued until no water remained. Solvent was then evaporated. The white solid was crushed and dried in vacuum over P2O5 for 48h [El Seoud and Fendler J Chem Soc, Faraday Trans I 71 452 /9751. 

The same PVP series were also tried for the dispersion polymerization of styrene in the ethanol medium by using AIBN as the initiator and aerosol OT as the costabilizer [84]. PVP K-15 usually yielded polymeric particles with a certain size distribution and some coagu-lum. The uniform products were obtained with PVP K-30 and PVP K-90 in the presence of the costabilizer. The tendencies for the variation of the final particle size with the stabilizer concentration and with the molecular weight of the stabilizer were consistent with those obtained for the dispersion polymerization of methyl methacrylate [84],... 

NaOH soln and w washing, 5.0 0.5% (3) HMX (MlL-H-45444A al by subtracting the binder percent from 100%, 95.0 0.5% (4) moisture content by the Karl Fischer method, 0.1 S% max (5) granulation, both Type I and II compns, gravimetrically after w/aerosol OT washing —... 

The carrier fluid was deionized water containing 1 gm/l of Aerosol OT and 1 g/l sodiiom nitrate. Compared to the use of potassium nitrate as electrolyte, suggested by Coll et al. (lO), the carrier solvent used in this investigation has much better clarity and at room temperature has no tendency to precipitate the surfactant. ... 

Di(2-ethylhexyl)sodium sulfosuccinate (diisoocytyl sulfosuc-cinate. Aerosol OT, AOT) was obtained from Aldrich and purified by... 

Figure 1. Anionic surfactant aerosol OT for a microemulsion preparation.

Six control sample jars of 0.01% Aerosol OT detergent in distilled water solution (200 mL each) were prepared at each site on sampling days 1,14 and 28 by dislodging leaf disks taken from the untreated control area. Triplicate samples were fortified at each of two concentrations. Fortification levels were 50 and 400 qg of oxamyl per sample. 

In the past few years, a range of solvation dynamics experiments have been demonstrated for reverse micellar systems. Reverse micelles form when a polar solvent is sequestered by surfactant molecules in a continuous nonpolar solvent. The interaction of the surfactant polar headgroups with the polar solvent can result in the formation of a well-defined solvent pool. Many different kinds of surfactants have been used to form reverse micelles. However, the structure and dynamics of reverse micelles created with Aerosol-OT (AOT) have been most frequently studied. AOT reverse micelles are monodisperse, spherical water droplets [32]. The micellar size is directly related to the water volume-to-surfactant surface area ratio defined as the molar ratio of water to AOT,... 

FIG. 4 Time-resolved fluorescence Stokes shift of coumarin 343 in Aerosol OT reverse micelles, (a) normalized time-correlation functions, C i) = v(t) — v(oo)/v(0) — v(oo), and (b) unnormalized time-correlation functions, S i) = v i) — v(oo), showing the magnitude of the overall Stokes shift in addition to the dynamic response, wq = 1.1 ( ), 5 ( ), 7.5 ( ), 15 ( ), and 40 (O) and for bulk aqueous Na solution (A)- Points are data and lines that are multiexponential fits to the data. (Reprinted from Ref 38 with permission from the American Chemical Society.)... 

Surfactants employed for w/o-ME formation, listed in Table 1, are more lipophilic than those employed in aqueous systems, e.g., for micelles or oil-in-water emulsions, having a hydrophilic-lipophilic balance (HLB) value of around 8-11 [4-40]. The most commonly employed surfactant for w/o-ME formation is Aerosol-OT, or AOT [sodium bis(2-ethylhexyl) sulfosuccinate], containing an anionic sulfonate headgroup and two hydrocarbon tails. Common cationic surfactants, such as cetyl trimethyl ammonium bromide (CTAB) and trioctylmethyl ammonium bromide (TOMAC), have also fulfilled this purpose however, cosurfactants (e.g., fatty alcohols, such as 1-butanol or 1-octanol) must be added for a monophasic w/o-ME (Winsor IV) system to occur. Nonionic and mixed ionic-nonionic surfactant systems have received a great deal of attention recently because they are more biocompatible and they promote less inactivation of biomolecules compared to ionic surfactants. Surfactants with two or more hydrophobic tail groups of different lengths frequently form w/o-MEs more readily than one-tailed surfactants without the requirement of cosurfactant, perhaps because of their wedge-shaped molecular structure [17,41]. 

In n-octane/aqueous systems at 27°C, TRS 10-80 has been shown to form a surfactant-rich third phase, or a thin film of liquid crystals (see Figure 1), with a sharp interfacial tension minimum of about 5x10 mN/m at 15 g/L NaCI concentration f131. Similarly, in this study the bitumen/aqueous tension behavior of TRS 10-80 and Sun Tech IV appeared not to be related to monolayer coverage at the interface (as in the case of Enordet C16 18) but rather was indicative of a surfactant-rich third phase between oil and water. The higher values for minimum interfacial tension observed for a heavy oil compared to a pure n-alkane were probably due to natural surfactants in the crude oil which somewhat hindered the formation of the surfactant-rich phase. This hypothesis needs to be tested, but the effect is not unlike that of the addition of SDS (which does not form liquid crystals) in partially solubilizing the third phase formed by TRS 10-80 or Aerosol OT at the alkane/brine interface Til.121. 

Zulauf, M and Eicke, H.F. "Inverted Micelles and Microemulsions in the Ternary System H20/Aerosol OT/Isooctane as Studied by Photon Correlation Spectroscopy," J. Phvs. Chem.. 1979, 82(4), 480 486. 

Arriagada, F.J., and Osseo-Asare, K. (1995) Synthesis of nanosize silica in aerosol OT reverse microemulsions./. Colloid Interface Sci. 170, 8-17. 

Indicator equilibria Aerosol-OT, heptane. Apparent values of pKa and pKk + analysed in terms of ion exchange O. A. El Seoud et al., 1982 O. A. El Seoud and Chinelatto, 1983... 

Fe2 + /02 Air oxidation much faster in Aerosol-OT reverse micelles in cyclohexane and n-heptane than in H20 Inouye et al., 1982... 

Photo-induced proton transfer Aerosol-OT. The efficiency of proton transfer depends on HzO. Pyranine used as a fluorescent probe. Bardez et al., 1984... 

The behavior of metal ions in reversed micelles may be more interesting, since the reversed micelle provides less solvated metal ions in its core (Sunamoto and Hamada, 1978). Through kinetic studies on the hydrolysis of the p-nitrophenyl ester of norleucine in reversed micelles of Aerosol OT and CC14 which solubilize aqueous cupric nitrate, Sunamoto et al. (1978) observed the formation of naked copper(II) ion this easily formed a complex with the substrate ester (formation constant kc = 108—109). The complexed substrate was rapidly hydrolyzed by free water molecules acting as effective nucleophiles. 

Figure 12.15. Fluorescence lifetime of IR-140 in Aerosol OT (AOT)/iso-octane microemulsions as a function of water pool size to, defined as the molar fraction of water to AOT. (From Ref. 58.)...

P. E. Zinsli, Inhomogeneous interior of aerosol OT microemulsions probed by fluorescence and polarization decay,/. Phys. Chem. 83, 3223-3231 (1979). 

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