Solution micelles

Goto, T., and Fukatsu, H. (1969). Cypridina bioluminescence VII. Chemiluminescence in micelle solutions — A model system for Cypridina bioluminescence. Tetrahedron Lett., pp. 4299-4302. 

Recent development of the use of reversed micelles (aqueous surfactant aggregates in organic solvents) to solubilize significant quantities of nonpolar materials within their polar cores can be exploited in the development of new concepts for the continuous selective concentration and recovery of heavy metal ions from dilute aqueous streams. The ability of reversed micelle solutions to extract proteins and amino acids selectively from aqueous media has been recently demonstrated the results indicate that strong electrostatic interactions are the primary basis for selectivity. The high charge-to-surface ratio of the valuable heavy metal ions suggests that they too should be extractable from dilute aqueous solutions. 

The solvation dynamics of the three different micelle solutions, TX, CTAB, and SDS, exhibit time constants of 550, 285, 180 ps, respectively. The time constants show that solvent motion in these solutions is significantly slower than bulk water. The authors attribute the observed time constants to water motion in the Stern layer of the micelles. This conclusion is supported by the steady-state fluorescence spectra of the C480 probe in these solutions. The spectra exhibit a significant blue shift with respect the spectrum of the dye in bulk water. This spectral blue shift is attributed to the probe being solvated in the Stern layer and experiencing an environment with a polarity much lower than that of bulk water. 

This work also shows that the time constants for the ionic surfactant micelle solutions are twice as fast as the TX solution time constant. Differences between the Stern layers of the micelles appear to be the charge of the surfactant polar headgroups and the presence of counterions. However, these differences do not account for the observed dynamics. Since the polar headgroups and counterions should interfact more strongly with the water molecules, the water motion at the interface should be slower. This view is supported by recent investigations where systematic variation of surfactant counter-... 

Shear-banded Flow in Wormlike Micelle Solutions... 

We found that the negatively charged surfactant, sodium laurel sulfate, can be successfully substituted for the serum proteins used previously. In low ionic strength solutions, the cmc of the surfactant is 8.1 mM [577]. We explored the use of both sub-CMC (data not shown) and micelle-level concentrations. Saturated micelle solutions are most often used at pION. 

The doxylstearates may be prepared as concentrated (e. g. 0.3 M) methanolic stock solutions. They should be added such that their final concentration in the micelle solution is about one spin label per micelle. When possible, the spin label should be added to the micelle solution before the peptide to ensure that it integrates into the micelles properly and does not bind specifically with the peptide. 

Photo-induced electron transfer from ferrocene, Fe1, to CCl has been observed in micelle solution at low concentrations... 

If the ideas of Marrucci [69] are correct and the non-monotonic predictions of the simple Doi-Edwards theory need to be modified in the case of polymer melts (for a recent development see [78]), then an explanation will be required for the apparent difference at high shear rates between melts and wormlike micelle solutions. There is also evidence that ordinary entangled polymer solutions do exhibit non-monotonic shear-stress behaviour [79]. As in the field of linear deformations, it may be that a study of the apparently more complex branched polymers in strong flows may shed light on their deceptively simple linear cous-... 

FIGURE 1.2. Formation of nanoparticles of metal oxide by reverse micelle method. A solution of inverse micelles is first formed by adding a long-chain alkylamine to a toluene solution. A small amount of water is trapped in the reverse micelle core. Mixing the reverse micelle solution with an aluminum alkoxy amine adduct results in hydrolysis of the aluminum alkoxide adduct and formation of nano-sized particles of aluminum oxyhydroxide after drying. These particles are shown in the SEM picture above. 

Micelle solutions of PlPAAm-Ci8H35 was prepared by direct dissolution of the polymer in cold water (4°C) due to its good water solubility [23]. Each solution of PIPAAm-PSt, PlPAAm-PBMA, and PIPAAm-PLA was prepared by dissolving each copolymer in DMF, A-ethylacetamide, and DMAc, respectively. The solutions were put into a dialysis bag (MWCO = 13,000) and dialyzed against distilled water at 10°C, 20°C, and 4°C, respectively, for 24 hours. The micelles were purified with ultrafiltration membrane of 200,000 molecular weight cut off at 4°C. The aqueous solution was lyophilized to leave a white powder of micelles. 

Chu, W. and Jafvert, C.T. Photodechlorination of polychlorobenzene congeners in surfactant micelle solutions, Environ. Sci Technol, 28(13) 2415-2422, 1994. 

The amount of water solubilized in a reverse micelle solution is commonly referred to as W, the molar ratio of water to surfactant, and this is also a good qualitative indicator of micelle size. This is an extremely important parameter since it will determine the number of surfactant molecules per micelle and is the main factor affecting micelle size. For an (AOT)/iso-octane/H20 system, the maximum Wq is around 60 [16], and above this value the transparent reverse micelle solution becomes a turbid emulsion, and phase separation may occur. The effect of salt type and concentration on water solubilization is important. Cations with a smaller hydration size, but the same ionic charge, result in less solubilization than cations with a large hydration size [17,18]. Micelle size depends on the salt type and concentration, solvent, surfactant type and concentration, and also temperature. 

The number of polymer particles is the prime determinant of the rate and degree of polymerization since it appears as the first power in both Eqs. 4-5 and 4-7. The formation (and stabilization) of polymer particles by both micellar nucleation and homogeneous nucleation involves the adsorption of surfactant from the micelles, solution, and monomer droplets. The number of polymer particles that can be stabilized is dependent on the total surface area of surfactant present in the system asS, where as is the interfacial surface area occupied by a surfactant molecule and S is the total concentration of surfactant in the system (micelles, solution, monomer droplets). However, N is also directly dependent on the rate of radical generation. The quantitative dependence of N on asS and R,- has been derived as... 

This method involves formation of reverse micelles in the presence of surfactants at a water-oil interface. A clear homogeneous solution obtained by the addition of another amine or alcohol-based cosurfactant is termed a Microemulsion. To a reverse micelle solution containing a dissolved metal salt, a second reverse micelle solution containing a suitable reducing agent is added reducing the metal cations to metals. The synthesis of oxides from reverse micelles depends on the coprecipitation of one or more metal ions from... 

Figure 4.4 Sudan yellow is a water-insoluble dye, seen at the bottom of the cylinder on the left but fully dissolved in the micelle solution on the right.

On the other hand, this azo form was observed in other surfactant micelle solutions such as sodium laurate (11) and nonionic surfactants (16). The maximal absorption wavelength is at 535 nm (quinoidal form) in the SDS solution, while at 450 nm (azo one) in the CmPOEn soutlon. 

In forming a mixed micelle, solute 3 will shift the CMC of solute 2 to lower values, and this will be reflected In the apparent molar properties of solute 3 In the CMC region of solute 2. 

The expansion of the film with Increasing acidity of the substrate may be due to the competition of counterions at the interface. The swamping amount of H ions in low pH subsolution competes with Na ions at the negatively charged interface. Such competition has been shown to exist between H ions and K" " ions at the negatively charged micelle-solution interface (11). Studies on the counterion effects in sodium docosyl sulfate monolayers (, 12) have shown that the film expansion follows the sequence Li > Na > K ". It follows that H" should give rise to the most expanded film. 

Replace inlet and outlet with micelle solution Reverse polarity... 

Other methods to prepare solid micelle dispersion, such as spray drying of a drug containing micelle solution onto solid core materials or solvent emulsiLcation technique to prepare solid lipid nanoparticles, can be found in literature (Karmazina, 1997 Burruano et al., 1999 Luo et al., 2006 Radomska-Soukharev et al., 2006). 

It implied that the motion of P P is suppressed by the microviscosity created by hydrophobic contracted polymer chain aggregation. On the other hand, the ryjda jj of PQ3P dissolved in PIPAAm-b-PBMA micelle solutions were markedly lowerthan those of PIPAAm solutions overthe entire temperature region owing to highly compact cores of aggregated PBMA chains. 

Soo et al. (2002) studied tliB vitro release of hydrophobic Luorescent probes from PEO-b PCL micelles. Micelle solutions were placed in dialysis bags (MWCO 50,000) in a stirred water bath with a constant overLow of distilled water. This maintained the release environment at near perfect sink conditions, so the limited solubility ofthe probes in the medium did not affect release kinetics. Release was determined by removing aliquots ofthe dialysis bag contents and measuring Luorescently. Soo et al. found an initial burst release of probe followed by slow diffusional release. For the probes studies, benzopyrene and Cell-Tracker-CM-Dil, diffusion constants were ofthe order 10"15 cnnP/s. 

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