Water nonionic surfactant

Benton, W.J. Raney, I.H, Miller, C.A. Enhanced Videomicroscopy of Phase Transitions and Diffusional Phenomena in Oil-Water-Nonionic Surfactant Systems, paper presented at the National AIChE Meeting, March 1985, Houston, Texas. 

A considerable amount of experimental work has been carried out on the so-called gel emulsions of water/nonionic surfactant/oil systems [9-14, 80, 106, 107]. These form in either the water-rich or oil-rich regions of the ternary phase diagrams, depending on the surfactant and system temperature. The latter parameter is important as a result of the property of nonionic surfactants known as the HLB temperature, or phase inversion temperature (PIT). Below the PIT, nonionic surfactants are water-soluble (hydrophilic form o/w emulsions) whereas above the PIT they are oil-soluble (hydrophobic form w/o emulsions). The systems studied were all of very high phase volume fraction, and were stabilised by nonionic polyether surfactants. 

Similar attempts were made by Likhtman et al. [13] and Reiss [14]. Reference 13 employed the ideal mixture expression for the entropy and Ref. 14 an expression derived previously by Reiss in his nucleation theory These authors added the interfacial free energy contribution to the entropic contribution. However, the free energy expressions of Refs. 13 and 14 do not provide a radius for which the free energy is minimum. An improved thermodynamic treatment was developed by Ruckenstein [15,16] and Overbeek [17] that included the chemical potentials in the expression of the free energy, since those potentials depend on the distribution of the surfactant and cosurfactant among the continuous, dispersed, and interfacial regions of the microemulsion. Ruckenstein and Krishnan [18] could explain, on the basis of the treatment in Refs. 15 and 16, the phase behavior of a three-component oil-water-nonionic surfactant system reported by Shinoda and Saito [19],... 

Fig. 1. Change of the phase volumes caused by variations of the oil component in the system oil-water-nonionic surfactant (redrawn from [8]). The micro emulsions were used as reaction media for the reaction between sodium phenoxide and 1-bromooctane to give 1-phenoxyoc-tane...

An attempt was also made to accelerate the same reaction performed in a microemulsion based on water, nonionic surfactant and hydrocarbon oil [9]. The reaction was performed in a Winsor III system and the same Q salt, tetra-butyl ammonium hydrogen sulfate, was added to the formulation. In this case the addition of the phase transfer catalyst gave only a marginal increase in reaction rate. Similar results have been reported for an alkylation reaction performed in different types of micellar media [52]. The addition of a Q salt gave no effect for a system based on cationic surfactant, a marginal increase in rate for a system based on nonionic surfactant and a substantial effect when an anionic... 

Benton, W.J., Raney, K.H., and Miller, C.A., Enhanced videomicroscopy of phase transitions and diffusional phenomena in oil-water-nonionic surfactant systems, J. Colloid Interface ScL, 110, 363, 1986. 

Solans, C., Garcia Dominguez, J. and Friberg, S.E. (1985) Evaluation of textile detergent efficiency of microemulsions in systems of water, nonionic surfactant and hydrocarbon at low temperature. /. Disp. Set. TechnoL, 6, 523. 

Kunieda, H. and Haishima, K. (1990) Overlapping of 3-phase regions in a water nonionic surfactant triglyceride system. /. Colloid Interface Sci., 140(2), 383-390. 

Kunieda H, Yano N, Solans C. The stability of gel-emulsions in a water/ nonionic surfactant/oil system. Colloids and Surf 1989 36 313-322. 

Research on microemulsions was a major topic in his scientific activity, since the earlier work under Prof. Shinoda s supervision [1, 2], through his entire scientific career. First the attention was focused to find the conditions to produce three-phase equilibria (balanced conditions) in both ionic [9-12] and nonionic [13-17] surfactant systems. In this context it was shown that the effect of temperature in ionic surfactant systems is opposite to that in polyoxyethylene-type nonionic surfactants [10] and that both types of surfactant systems display similarities in phase behavior [18]. The most detailed phase equilibria of a water/ nonionic surfactant/ahphatic hydrocarbon system around the HLB temperature (Figure 2) was reported in 1982 [16]. 

K. (1988) Two types of surfactant phases and four coexisting liquid phases in a water/nonionic surfactant/ triglyceride/ hydrocarbon system. 

Kunieda, H. (1989) Phase behaviors in water/nonionic surfactant/hydrocarbon and water/nonionic surfactant/ amphiphilic oil system. J. Colloid Interface Sci., 133, 237-243. 

It is a characteristic feature of ionic surfactant micelliza-tion that the CMC is, to a first approximation, independent of the temperature. The temperature-dependence of the CMC of sodium dodecyl sulfate (SDS), displayed in Figure 19.6, is a good illustration of this. The CMC varies in a non-monotonic way by ca. 10-20% over a wide range. The shallow minimum at around 25°C can be compared with a similar minimum in the solubility of hydrocarbons in water. Nonionic surfactants of the polyoxyethylene type deviate from this behaviour and show typically a monotonic, and much more pronounced, decrease in CMC with increasing temperature. As will be discussed briefly at the end of this chapter, this class of nonionics behaves differently from other surfactants with respect to temperature effects. 

Solans, C, Azemar, N., Parra, J., and Calbet, J., Phase behavior and detergency in water/nonionic surfactant/hydrocarbon systems. Proceedings CESIO 2nd World Surfactants Congress, vol. 2, Paris, 1988, p. 421 ff. 

As mentioned in Chapter 4 (Section 12), extensive spontaneous emulsification of water in the oil phase is also observed when water-nonionic surfactant mixtures contact oil at temperatures above the PIT. Here the surfactant is preferentially soluble in oil, so that one has a solute diffusing into the phase in which it is more soluble, as in Figure 6.23. A plausible diffusion path has been proposed for this situation (Benton et al., 1986). One difference is that, as might be expected, the emulsions in the oil-water-surfactant systems arc considerably more stable than in the oil-water-alcohol systems. 

Schirmer, C., Liu, Y., Touraud, D., Meziani, A., Pulvin, S., and Kunz, W. (2002). Horse liver alcohol dehydrogenase as a probe for nanostructuring effects of alcohols in water/nonionic surfactant system. J. Phys. Chem. B, 106, 7414—7421. 

Figure 4.4. Schematic phase diagrams as a function of temperature of the three binary mixtures, oil/water, water/nonionic surfactant and oil/nonionic surfactant, showing critical points (cps) and tie-lines within the 2 phase regions. Reproduced by permission of Wiley-VCH (redrawn from Kahlweit and Strey (25))...

Dorfler et al. systematically studied the phase behavior of quaternary systems, consisting of water, nonionic surfactants, a cosurfactant and a hydrocarbon, with regard to possible applications in the textile cleaning sector. As an example. Figure 12.19 shows the influence of the cosurfactant on the phase behavior of the water-oil-surfactant system. In this case the phase inversion range decreases by an average of about 5 K per added mol% cosurfactant. The extent of the three-phase zone is scarcely affected. 

FIGURE 21.1 Schematic representation of a typical phase diagram of a ternary water/nonionic surfactant/ oil system as a function of temperature and surfactant content at constant O/W weight ratio (/ ). O/W nanoemulsion formation paths by the PIT method are indicated by arrows. The process starts from a bicontinuous microemulsion (D), path (a) an inverse microemulsion (0 ), path (b, point 2 ) a lamellar liquid crystal (L ), path (b, point 2), and a three-phases region (W + D + O), path (c). (1) indicates compositions below the HLB temperature where all components are mixed and where O/W nano-emulsions are formed), (2) indicates compositions at the HLB temperature, and (3) indicates compositions above the HLB temperature. 

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