Micelle ionic strength effect

In equation (i )[Na ] is the total molar concentration of free sodiiam ions, [ SL j is the molar concentration of ionic Cj 2 25 S05J, and [SLS]jjj is the concentration of the SLS micelles. The corresponding ionic strengths are indicated in the fig ire heading. The capillary model can also be used to account for the ionic strength effects seen in Figure 2 and is discussed elsewhere (23). 

M. Arunyanart and L.J. Cline-Love, Influence of Micelles on Partitioning Equilibria of lonizable Species in LC pH and Ionic Strength Effects, Anal. Chem., 57 2837 (1985). 

Hamada, K., Ikeda, T., Kawai, T., Kon-No, K. Ionic strength effects of electrolytes on solubilized states of water in AOT reversed micelles. J. Colloid Interface Sci. 2001, 255(2), 166-170. 

From electrophoretic data for SLS micelles under various ionic conditions (22 ), values of 80 for the aggregation number and 23 for the effective charge of the kinetic micelles can be used. This gives the following formula for the eluant total ionic strength. 

Clustering in PS-[Ru]-PEO micelles was shown to be sensitive to temperature and ionic strength, as previously observed for covalent PS-PEO copolymer [131]. These effects were, however, more pronounced in the case of the metallosupramolecular copolymers, indicating a possible influence of the charged fois-2,2/ 6/,2/terpyridine-ruthenium(II) complexes [329]. 

Effect of salt type and concentration The ionic strength of the aqueous solution in eontaet with a reverse micelle phase affects protein partitioning in a number of ways [18,23]. The first is through modification of electrostatic interactions between the protein surface and the surfaetant head groups by modifieation of the eleetrieal double layers adjacent to both the eharged inner mieelle wall and the protein surface. The second effect is to salt out the protein from the mieelle phase because of the inereased propensity of the ionie speeies to migrate to the micelle water pool, reduee the size of the reverse mieelles, and thus displace the protein. 

The effects of the high ionic strength (3) appear to depend rather much on the details of the hydrolytic probe. For example, aqueous rate constants for 4-nitrophenyl 2,2-dichloropropionate 2 decrease as a function of added electrolyte (as typically happens), but the origin of this rate decrease by added electrolytes was interpreted to be different from the rate-retarding effect exerted by micelles based on activation parameter considerations. For another hydrolytic probe, phenyl chloro-formate lb, increasing electrolyte concentrations also decrease the rate of reaction, but this effect is negligible in comparison to the micellar rate effects. " ... 

Tengamnuay, P., and A.K. Mitra. 1990. Bile-salt fatty acid mixed micelles as nasal absorption promoters of peptides. I. Effects of ionic strength, adjuvant composition and lipid structure on the nasal absorption of [D-Arg2]kyotorphin. Pharm Res 7 127. 

By increasing the ionic strength, that is, the acid or metallic salt concentration, in the aqueous phase, the concentration of the extracted acid or salt in the organic phase increases and induces an increase in the attractions between reverse micelles (see below). Numerically, all the terms can be evaluated (7, 37, 83). It can then clearly be concluded that this effect is the origin of the third-phase formation. 

The comparison of CMC data in distilled vs. hard river water shows that the decrease in CMC with hardness has the order anionics cationics nonionics (Rosen et al., 1996). Hardness increases the dependence of the CMC on alkyl carbon chain length of CnE0mS04, indicating that in hard water the influence of additional carbon atoms is the same for CnE0mS04 as for CnEOm surfactants (Rosen et al., 1996). The influence of ionic strength on micellization of nonionic surfactants is due to a salting out effect of the hydro-phobic moiety of the surfactant molecule (Carala et al., 1994). 

An increase in the phenanthrene partition coefficient for SDS micelles is observed with increasing ionic strength at a fixed pH of 6 (Table 2). A conceptual model has been proposed to describe the effects of electrolyte addition on the partitioning of nonpolar compounds such as phenanthrene into the core (or deep region within the palisade layer) of ionic surfactant... 

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