Water three-component phase diagram

Figure 3.11 Schematic of the three-component phase diagram often used to rationalize the formation of water-precipitation phase separation membranes...

Figure 3.12 Membrane formation in water-precipitation membranes was first rationalized as a path through the three-component phase diagram from the initial polymer casting solution (A) to the final membrane (D) [24]...

Figure 3.13 The surface layer of water-precipitation membranes precipitates faster than the underlying substrate. The precipitation pathway is best represented by the movement of a line through the three-component phase diagram [27]...

The sulfones, sulfolane and 3-methylsulfolane, are shown to function quite well, as cosurfactants with CTAB, in the solubilization of both organophosphorus esters and betahalosulfides. For the organophosphate used, tributylphosphate, it is shown through pseudo-three-component phase diagrams that the sulfone functions as effectively as the alcohol in its role of cosurfactant. Solubilization of chloroethyl ethyl sulfide is less effective when the sulfone cosurfactant is used, but is still a dramatic enhancement over its solubility in water alone. The effect of added salt on the solubilization is reported, as well as the effect of changes in the surfactant-cosurfactant ratio. Preliminary quasielastic lightscattering measurements are also reported for these unconventional systems. 

The experimental procedures described in this paper are mainly concentrated on the preparation of membranes from various polymer-solvent systems by precipitation in a nonsolvent, generally water. The membranes are then characterized in terms of their transport properties and structures. Furthermore, the three-component phase diagrams are determined for various polymer-solvent-precipitant systems. 

Figure 11. Three-component phase diagram at 25 C at the systems poly-amide-NMP-water, polyamide-DMAC-water, polyamide-DMSO-water, and cellulose acetate-acetone-water.

From the phase behavior of both binary mixtures (water-amphiphile and oil— amphiphile), it is now possible to account, at least qualitatively, for the three-component phase diagram as a function of temperature. The presence of a haze point on the oil-amphiphile phase diagram (critical point a) at temperature Ta shows that the surfactant is more compatible with the oil at high than at low temperature. The presence of a cloud point on the water-amphiphile phase diagram (the lower critical point (>) at temperature Tjj shows that (at least in the neighborhood of the temperature domain) the amphiphile is less compatible with water at high than at low temperature. As a consequence (the other parameters being kept constant), the amphiphile behavior depends on temperature. 

If the temperature at which the phase diagram is recorded is above Ta (the haze point), a critical point CPa is present near the oil vertex (although pure amphiphile and pure oil are miscible, the presence of a small amount of water recalls the lack of compatibility between amphiphile and oil). If the temperature is below Ta, no critical point appears in the three-component phase diagram (it would be positioned at a negative water concentration). 

Three component triangular diagrams. Both Cowell et al. (1978) and Vincent et al. (1980) presented what they termed three component phase diagrams for aqueous systems composed of water (or electrolyte solution), free poly(oxyethylene) and polystyrene latex particles sterically stabilized by poly(oxyethylene). Such a diagram is reproduced in Fig. 16.7. 

Figure 20 A schematic representation of a three-component phase diagram for a surfactant-oil-water system. (From Ref. 36.)...

The common miscible processes can be generalized very loosely by the three-component phase diagram in Figure 5. The fluid which is miscible with both oil and water (or oil and gas) at the prescribed conditions is shown at the apex of the ternary diagram. 

Diethylene glycol monoalkyl ether was used as a cosurfactant in the formation of an oil-in-water styrene microemulsion. Sodium dodecyl sulphate was used as a surfactant. The pseudo three-component phase diagram, macroemulsion, microemulsion and lamellar gal phases, was constructed for the cosurfactants. A smaller number of latex particles nucleated than there were microemulsion droplets initially present. The diethylene glycol monoalkyl ether group of CiEj enhances the latex stability and the CiEj more effectively stabihses the styrene microemulsion and subsequent polymerisation compared with CiOH cosurfactants used as a comparison. 15 refs. 

Figure 1 shows a schematic representation of the pseudo three-component phase diagram of a surfactant/cosurfactant-oil-water system. Depending on formulas, fine oil droplets dispersed in the continuous aqueous phase [0/W (or direct) microemulsion] or fine water droplets dispersed in the continuous oily... 

Figure 6.1 shows a schematic representation of the pseudo three-component phase diagram of a typical (surfactant/cosurfactant)-oil-water system. Depending on formulas, fine oil droplets dispersed in the continuous aqueous phase [O/W (or direct) microemulsion] or water droplets in the continuous oily phase [W/O (or inverse) microemulsion] are obtained. Furthermore, the intermediate region between the OAV microemulsion phase and the W/O microemulsion phase is characterized by a bicontinuous microstructure in which the aqueous and oily microdomains are interconnected with each other [13, 14]. The presence of such a middle phase in the colloidal system was verified by literature data [15]. It was shown that the oil-water interfacial layer in the bicontinuous microstructure has a zero mean curvature (i.e., it is flat on the average), and this sponge-like microstructure is completely disor-... 

Teddy and Wheeler [201] have described the three-component phase diagram for the ammonium perfluorooctanoate/octanol-water system. The phase structure was determined by optical microscopy. Octanol was found to be four times less soluble in ammonium perfluorooctanoate solutions than in sodium oc-tanoate solutions. The low solubility of octanol was attributed to a low mutual solubility of fluorocarbon and hydrocarbon chains and not to different counterions, ammonium versus sodium. However, the ammonium counterion may have contributed to the high solubility of ammonium perfluorooctanoate in octanol. 

The effect of additives on mesophases of fluorinated surfactants has been studied by Tiddy and Wheeler [ 163] and Rosenblatt [176]. Tiddy and Wheeler described the effects of -octanol on the ammonium perfluorooctanoate-water system with a three-component phase diagram (Fig. 7.39). The main differences between phase diagrams for this system and that for sodium octanoate- octanol-water were related to mutual phobicity between fluorocarbon and hydrocarbon chains. Octanol was found to be less soluble in the aqueous micellar phase of ammonium perfluorooctanoate than that of sodium octanoate. However, ammonium perfluorooctanoate is more soluble in octanol than sodium octanoate. This solubility difference is probably related to the effect of counterions, as ammonium salts are usually more soluble in octanol than sodium salts. 

FIGURE 8.6 The surface layer of water-precipitated membranes precipitates faster than the underlying layer. The precipitation pathway is best represented by the movement of a line through the three-component phase diagram. SEM images were taken from a membrane prepared in PVDF/DMF/water system (own data). (Data from Baker, R.W., Membrane Technology and Applications, 3rd Edition, Wiley, Chichester, 2012. http //eu.wiley.com/ WileyCDA/WileyTitle/productCd-0470743727.html.)... 

Perhaps the most important one-component system for life on Earth is that of water. A simplified phase diagram for water is drawn in Figure 4.2. The three phases found are ice (sohd), water (liquid) and... 

A phase diagram is a map that indicates the areas of stability of the various phases as a function of external conditions (temperature and pressure). Pure materials, such as mercury, helium, water, and methyl alcohol are considered one-component systems and they have unary phase diagrams. The equilibrium phases in two-component systems are presented in binary phase diagrams. Because many important materials consist of three, four, and more components, many attempts have been made to deduce their multi-component phase diagrams. However, the vast majority of systems with three or more components are very complex, and no overall maps of the phase relationships have been worked out. 

The accompanying sketch qualitatively describes the phase diagram for the system nylon-6,6, water, phenol for T > 70°C.f In this figure the broken lines are the lines whose terminals indicate the concentrations of the three components in the two equilibrium phases. Consult a physical chemistry textbook for the information as to how such concentrations are read. In the two-phase region, both phases contain nylon, but the water-rich phase contains the nylon at a lower concentration. On this phase diagram or a facsimile, draw arrows which trace the following procedure ... 

Figure 6.4. Schematic phase diagram for a three-component (oil, water, surfactant) system showing some of the self-assembled structures which form in the various regions.

In 1959, J. H. Schulman introduced the term microemulsion for transparent-solutions of a model four-component system [126]. Basically, microemulsions consist of water, an oily component, surfactant, and co-surfactant. A three phase diagram illustrating the area of existence of microemulsions is presented in Fig. 6 [24]. The phase equilibria, structures, applications, and chemical reactions of microemulsion have been reviewed by Sjoblom et al. [127]. In contrast to macroemulsions, microemulsions are optically transparent, isotropic, and thermodynamically stable [128, 129]. Microemulsions have been subject of various... 

Temperature and pressure are the two variables that affect phase equilibria in a one-component system. The phase diagram in Figure 15.1 shows the equilibria between the solid, liquid, and vapour states of water where all three phases are in equilibrium at the triple point, 0.06 N/m2 and 273.3 K. The sublimation curve indicates the vapour pressure of ice, the vaporisation curve the vapour pressure of liquid water, and the fusion curve the effect of pressure on the melting point of ice. The fusion curve for ice is unusual in that, in most one component systems, increased pressure increases the melting point, whilst the opposite occurs here. 

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