The Influence of Third Components

There is a vast body of data concerning the influence of third components on surfactant liquid crystals. Because of the possible great complexity of the inherent mesophase behavior this array of data can appear to be enormously difficult to rationalize. However, if we can consider the simple concepts described above (micelle formation, micelle 

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THE INFLUENCE OF THIRD COMPONENTS COSURFACTANTS, MIXED SURFACTANTS, OILS, HYDROTROPES, ELECTROLYTES AND ALTERNATIVE SOLVENTS... 

There is a vast body of data concerning the influence of third components on surfactant liquid crystals. Because of the potentially great complexity of the inherent mesophase behaviour, this array of data can appear to be enormously difficult to rationalize. However, if we consider the simple concepts described above (micelle formation, micelle shape/packing constraints, volume fractions and the nature of intermicel-lar interactions), then a reasonably simplified picture emerges, at least for the water-continuous phases. This present section does not attempt to be comprehensive - it simply reports selected examples of behaviour to illustrate the general concepts. The simplest way to show the changes in mesophase behaviour is to employ ternary phase diagrams. The reader should recall that the important factors are (i) the behaviour as a function of surfactant/additive ratio, and (ii) the volume... 

Surfactants are widely recognized to enhance the aqueous solubility of many compounds which, by themselves, are poorly soluble in water. This phenomenon is termed solubilization [6] and is a very large subject that has been treated in Ref. 6 and elsewhere [7]. Solubilization will not be considered herein, as the present focus is on the solubility of surfactant compounds themselves. Some consideration will be given to the influence of third components on surfactant solubility, however. 

A book by Laugh in [76] is a very valuable reference on the aqueous phase behavior of surfactants. It covers this vast area of science from the viewpoints of the role of phase science within physical science, physical chemistry (thermodynamics of immiscibility, phase diagrams, the phase rule, characteristic features of surfactant phase behavior, kinetic and mechanistic aspects of surfactant phase behavior, relative humidity), structures and properties of surfactant phases, molecular correlations (surfactant and nonsurfactant behavior in amphiphilic molecules, hydrophilicity, lipophilicity, proximate and remote substituent effects, influence of third components on aqueous surfactant phase behavior), the relationship of the physical science of surfactants to their utility, and the history of surfactant phase science. 

V. THE CRYSTAL-LIQUID (KRAFFT) BOUNDARY INFLUENCE OF THIRD COMPONENTS... 

Only typical values are considered the inclusion of further data may expand the ranges given. In addition, the values are modified substantially by the environmental conditions. For example, the presence of third components in solution (e.g., inorganic electrolytes) may influence the observed volumes (especially of strong polyelectrolytes, such as nucleic acids or charged polyamino acids). 

Po is the standard pressure and px is the partial pressure of component X. Rearrangement of Eq. (56) leads to a third-order equation in t, which can be solved iteratively. Notice that the pressures used in Eq. (55) should actually be replaced by activities, implying that they should be corrected by their respective fugacity coefficients, which are of importance when dealing with methanol and water. We leave it as an exercise for the reader to judge the influence of such effects, utUizing the relation between pressure and activity given in Eq. (39) of Chapter 2. 

The analyzer contains three sensitive elements (thin films of zinc oxide) two elements are used in the measurements, whereas the third one is isolated hrom the atmosphere and serves to compensate for time and temperature drifts and to exclude the influence from molecular components of the environment. 

Since an ion is subject to a resuitant or net force, its drift velocity also must be a net drift veiocity resolvable into components. Furthermore, since each component force shouid produce a component of the overaii drift velocity, there must be three components of the net drift veiocity. The first component, which will be designated v°, is the direct result of the externally applied field only and excludes the influence of interactions between the ion and the ionic cloud the second is the electrophoretic component Vg and arises from the participation of the ion in the electrophoretic motion of its cioud finaiiy, the third component is the reiaxation field component originating from the reiaxation force that retards the drift of the ion. Since the electrophoretic and reiaxation forces act in a sense opposite to the externally applied eiectric field, it follows that the electtophoretic and relaxation components must diminish the overall drift velocity (Fig. 4.91), i.e.,... 

Under the influence of an optical pump, the molecular angular distribution described by Equation 12.4 can be considerably modified. In turn, this results in modification of the X ijkl tensor components. Further, we discuss the influence of a polarized pump beam on third-order nonlinear phenomena such as third harmonic generation (THG) [(described by (-3a),ft>,w,a>) coefficient], electric field induced second harmonic generation (EFISH) [x / kl -2(0, (o, o), 0)] and degenerate four-wave mixing (DFWM) X kl ... 

Besides these thermodynamic criteria, the most common approach used in the literature is based on the operation at pressures above the binary (liquid - SC-CO2) mixture critical point, completely neglecting the influence of solute on VLEs of the system. But, the solubility behavior of a binary supercritical COj-containing system is frequently changed by the addition of a low volatile third component as the solute to be precipitated. In particular, the so-called cosolvency effect can occur when a mixture of two components solvent+solute is better soluble in a supercritical solvent than each of the pure components alone. In contrast to this behavior, a ternary system can show poorer solubility compared with the binary systems antisolvent+solvent and antisol-vent+solute a system with these characteristics is called a non-cosolvency (antisolvent) system. hi particular, in the case of the SAS process, they hypothesize that the solute does not induce cosolvency effects, because the scope of this process lies in the use of COj as an antisolvent for the solute, inducing its precipitation. 

The problem of the influence of a third component on the mutual solubility of two liquids may be treated as an application of the critical solution phenomena of ternary systems. 

These relations then enable us to calculate ST/So g, that is to say the influence of the third component on the critical temperature. 

Let us consider a laminar steady-state fluid flow in a rectilinear tube of constant cross-section. The fluid streamlines in such systems are strictly parallel (we neglect the influence of the tube endpoints on the flow). We shall use the Cartesian coordinates X, Y, Z with Z-axis directed along the flow. Let us take into account the fact that the transverse velocity components of the fluid are zero and the longitudinal component depends only on the transverse coordinates. In this case, the continuity equation (1.1.1) and the first two Navier-Stokes equations in (1.1.2) are satisfied automatically, and it follows from the third equation in (1.1.2) that... 

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