Sodium perfluorooctanoate surfactant mixtures

Partial or total fluorination has striking effects on the CMC. Thus while perfluorinated compounds have much lower CMCs than the corresponding hydrocarbon surfactants (as an example the CMC is 0.030 M for sodium perfluorooctanoate and 0.38 M for sodium octanoate), partial fluorination increases the CMC. The strong deviation from an ideal behavior is illustrated in Fig. 2.425. A markedly nonideal behavior is also found in mixtures of hydrocarbon and fluorocarbon surfactants26. ... 

Trehalose tetraesters characterised by ID and 2D H and C NMR and ESI-MS as biosurfactants (rather than cryoprotectants) were isolated from a soil strain of Micrococcus luteus. Solubilisation of phenol within mieellar aggregates of hexadecyltrimethylammonium bromide (HTAB) in aqueous solutions were investigated by H NMR in D20. The synthesis and properties of non-cytotoxic carboxymethylcellulose-chitosan hydrogels modified with poly(ester-urethane) was reported. 2D NOE NMR gave new insights into the interactions between polyamidoamine dendrimers and different surfactants including SDS and dodecyltrimethylammonium bromide. The ability of a- and (3-CDs to disrupt a surfactant mixed micelle of an equimolar mixture of octyltriethylammonium bromide (OTEAB) and sodium perfluorooctanoate (SPFO) was studied by H and F NMR. The effect of ethanol on the micellization of SDS (anionic... 

A keen interest in microemulsions of fluorocarbons in water was kindled by the need for synthetic oxygen earners in blood (see Section 10.4). Gerbacia and Rosano [121] prepared a stable fluorocarbon emulsion using a mixture of fluorinated and hydrocarbon-type nonionic surfactants. The droplet size was not determined, however, and the emulsions were not characterized. Oliveros et al. [122] prepared perfluorinated microemulsions consisting of four components (1) sodium perfluorooctanoate, an anionic fluorinated surfactant (2) 2,2,3,3,4,4,4-heptafluoro-1-butanol (3) perfluorohexane (4) water. The pseudoternary-phase diagram (Fig. 4.40) shows two regions. Mi and Mi, of respective W/0 and OAV microemulsions [122]. These optically transparent microemulsions were characterized by nuclear magnetic resonance spectroscopy. 

Guo et al. [80] have studied mixtures of sodium perfluorooctanoate (SPFO) with a nonionic, an amphoteric, and a cationic hydrocarbon-type surfactant by NMR and surface tension meaurements ... 

Treiner and co-workers [81] measured partitioning of 1-pentanol to elucidate the micellar composition of two aqueous mixed anionic surfactant solutions (sodium decyl sulfate -I- sodium peifluorooctanoate and sodium dodecyl sulfate + sodium perfluorooctanoate). The partition coefficient exhibited a maximum in hydrocarbon-rich mixtures in both mixed micellar solutions. The synergistic effect was attributed to hydrocarbon-fluorocarbon repulsive interaction and found to be in accord with the regular solution model using interaction parameters determined for binaiy surfactant solutions. 

Klevens and Raison [65] studied micellization of sodium dodecyl sulfate and perfluorooctanoic acid. Their data have been reviewed by Mukerjee and My-sels [66], who concluded that partially fluorinated surfactants behave like mixtures of fluorinated and hydrocarbon-based surfactants. 

The kinetics of micellization of perfluorinated surfactants has been investigated by Hoffmann and co-workers [74-80] by pressure jump and a shock wave method with conductivity detection [74-80]. Hoffmann and Ulbricht [75] also used a temperature jump relaxation technique [81] with optical detection, utilizing a pH indicator (thymol blue) to observe relaxation processes of a 1 1 mixture of perfluorooctanoic acid and its sodium salt. For micellar systems in which fast relaxation times could be measured, the parameters k /n, k lcr, a ln, and k /n were calculated. 

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