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Interfacial tension miscibility

In supported liquid membranes, a chiral liquid is immobilized in the pores of a membrane by capillary and interfacial tension forces. The immobilized film can keep apart two miscible liquids that do not wet the porous membrane. Vaidya et al. [10] reported the effects of membrane type (structure and wettability) on the stability of solvents in the pores of the membrane. Examples of chiral separation by a supported liquid membrane are extraction of chiral ammonium cations by a supported (micro-porous polypropylene film) membrane [11] and the enantiomeric separation of propranolol (2) and bupranolol (3) by a nitrate membrane with a A/ -hexadecyl-L-hydroxy proline carrier [12]. [Pg.130]

In addition to the environmentally benign attributes and the easily tunable solvent properties, other important characteristics such as low interfacial tension, excellent wetting behavior, and high diffusion coefficients also make SCCO2 a superior medium for the synthesis of nanoscale materials [2]. Previous works on w/c RMs showed that conventional hydrocarbon surfactants such as AOT do not form RMs in scCOi [3] AOT is completely insoluble in CO2 due to the poor miscibility of the alkyl chains with CO2, restricting the utilization of this medium. Recently, we had demonstrated that the commonly used surfactant,... [Pg.729]

A similar technique, the so-called spontaneous emulsification solvent diffusion method, is derived from the solvent injection method to prepare liposomes [161]. Kawashima et al. [162] used a mixed-solvent system of methylene chloride and acetone to prepare PLGA nanoparticles. The addition of the water-miscible solvent acetone results in nanoparticles in the submicrometer range this is not possible with only the water-immiscible organic solvent. The addition of acetone decreases the interfacial tension between the organic and the aqueous phase and, in addition, results in the perturbation of the droplet interface because of the rapid diffusion of acetone into the aqueous phase. [Pg.275]

Petroleum recovery typically deals with conjugate fluid phases, that is, with two or more fluids that are in thermodynamic equilibrium. Conjugate phases are also encountered when amphiphiles fe.g.. surfactants or alcohols) are used in enhanced oil recovery, whether the amphiphiles are added to lower interfacial tensions, or to create dispersions to improve mobility control in miscible flooding 11.21. [Pg.292]

Cosolvent flooding is an experimental method for removing DNAPLs trapped below the water table. It involves injecting a highly concentrated aqueous mixture of solvents, such as alcohols, a chemical that is miscible with either phase in the aquifer. This process has the tendency to increase or enhance DNAPL (or LNAPL) solubility greatly, and to reduce the NAPL-water interfacial tension. Depending upon the phase behavior between the cosolvent and NAPL, a cosolvent flood can be developed to emphasize either enhanced dissolution (i.e., use of methane flooding for the dissolution of TCE) or NAPL mobilization. [Pg.238]

Miscible organic solutes modify the solvent properties of the solution to decrease the interfacial tension and give rise to an enhanced solubility of organic chemicals in a phenomenon often called cosolvency . According to theory, a miscible organic chemical such as a short chain alcohol will have the effect of modifying the structure of the water in which it is dissolved. On the macroscopic scale, this will manifest itself as a decrease in the surface tension of the solution [238,246]. [Pg.143]

The units of interfacial tension are identical for surface tension, i.e., dyn/cm. Interfacial tension values of organic compoimds range from zero for completely miscible liquids (e.g., acetone, methanol, ethanol) up to the surface tension of water at 25 °C which is 72 dyn/cm (Lyman et al., 1982). Interfacial tension values may be affected by pH, surface-active agents, and dissolved gases (Schowalter, 1979). Most of the interfacial tension values reported in this book were obtained from Dean (1987), Demond and Lindner (1993), CHRIS (1984), and references cited therein. [Pg.16]

Compatibilizers are compounds that provide miscibility or compatibility to materials that are otherwise immiscible or only partially miscible yielding a homogeneous product that does not separate into its components. Typically, compatibilizers act to reduce the interfacial tension and are concentrated at phase boundaries. Reactive compatibilizers chemically react with the materials they are to make compatible. Nonreactive compatibilizers perform their task by physically making the various component materials compatible. [Pg.492]

It would be of considerable interest to have data for the surface and interfacial tensions of a pair of liquids such as nicotine and water which are miscible in all proportions except within a definite temperature range. Here we should expect to find curves of the type shown in the figure, where a and h represent the surface tensions of the two phases within the critical region and c their interfacial tension. The latter has no meaning either above or below the critical temperatures and must have a maximum at some intermediate point. [Pg.101]

If the original liquids are again partially miscible, and the added component soluble in either the mutual solubility may be increased if so the interfacial tension will probably diminish whatever may be the effect on the surface tensions of the two pure liquids. Clearly, if sufficient of the third component be added to make the two phases completely soluble the interfacial tension must disappear altogether. [Pg.105]

Movements in the plane of the interface result from local variations of interfacial tension during the course of mass transfer. These variations may be produced by local variations of any quantity which affects the interfacial tension. Interfaeial motions have been ascribed to variations in interfacial concentration (H6, P6, S33), temperature (A9, P6), and electrical properties (AlO, B19). In ternary systems, variations in concentration are the major factor causing interfacial motion in partially miscible binary systems, interfacial temperature variations due to heat of solution effects are usually the cause. [Pg.246]

Analyzes the ability of a paste to spread over a biological surface and calculates the interfacial tension between the two [110], The tension is considered proportional to X1/2, where X is the Flory polymer-polymer interaction parameter. Low values of this parameter correspond to structural similarities between polymers and an increased miscibility... [Pg.178]

The condition for complete miscibility of two liquids is simply that the interfacial tension between them should be zero or negative. If this is so, then the molecular forces no longer operate to keep the liquids apart, for each liquid attracts the molecules of the other as much as, or more than, they are attracted by their own liquid. WAB becomes equal to, or greater than, Ya+Yb > and therefore molecules move across from one liquid to the other quite freely. [Pg.8]

The factors affecting the design of mechanically agitated liquid-liquid reactors are the miscibility of the liquid phases, the interfacial tension, and the densities and viscosities of the liquid phases, as well as the density and viscosity differences between the two liquids. As shown in Fig. 21, a variety of stirrer configurations are available to carry out liquid-liquid reactions. [Pg.108]

Fig. 2. Schematic description of a thin film containing two constituents A,B on a substrate (cross-hatched) indicating various possibilities of dewetting, depending on interfacial tensions between A-rich and B-rich phases and the solid substrate (yAS> Ybs) and the vapor (yAV, yBV) and the interfacial tension between coexisting A-rich and B-rich fluid phases (yAB). In case a, the A-rich phases wets the substrate and forms a thin A-rich layer coating the substrate, while the B-rich phase on top does not wet this layer (contact angle 0 being nonzero). In case b, the A,B mixture is miscible (yAb<0) but does not wet the substrate. In case c, neither phase wets the substrate... Fig. 2. Schematic description of a thin film containing two constituents A,B on a substrate (cross-hatched) indicating various possibilities of dewetting, depending on interfacial tensions between A-rich and B-rich phases and the solid substrate (yAS> Ybs) and the vapor (yAV, yBV) and the interfacial tension between coexisting A-rich and B-rich fluid phases (yAB). In case a, the A-rich phases wets the substrate and forms a thin A-rich layer coating the substrate, while the B-rich phase on top does not wet this layer (contact angle 0 being nonzero). In case b, the A,B mixture is miscible (yAb<0) but does not wet the substrate. In case c, neither phase wets the substrate...
Due to the fact that interfacial tension becomes zero at the critical point of the mixture, above which complete miscibility occurs, the relatively high value of interfacial tension at 30.5 MPa and 313 K (1.88 mN/m ) indicates that the system investigated in this work is still relatively far from its critical pressure. This observation is also valid for all nine temperatures investigated and agrees with the phase equilibrium measurements shown in Figure 4. [Pg.660]

In the field of thermoplastic immiscible blends, the emulsifying activity of block copolymers has been widely used to solve the usual problem of large immiscibility associated with high interfacial tension, poor adhesion and resulting in poor mechanical properties. An immiscible thermoplastic blend A/B can actually be compatibilised by adding a diblock copolymer, poly(A-b-B) whose segments are chemically identical to the dissimilar homopolymers, or poly(X-b-Y) in which each block is chemically different but thermodynamically miscible with one of the blend component. Theoretical... [Pg.98]

The capillary tube method can be used to determine the interfacial tension Gi2 between two immiscible, or partially miscible liquids (Fig. 12.VIII G.) The drop weight method ( 14.VIIIG) has also been used. Bartell, Case, and Brown measured the interfacial tensions between mercury and organic liquids by the capillary tube and the drop weight methods and found that the two methods gave the same results. Some values for water are also given. Values in dynes/cm. are ... [Pg.169]

The relations between the surface tensions and interfacial tension given in 9.VIII G apply strictly only to immiscible liquids when the liquids are partly miscible, the surface tensions change. For this case Antonoff proposed a rule which is generally understood (but perhaps not correctly) to mean that the interfacial tension between the two saturated liquid layers is equal, or very approximately equal, to the difference between the surface tensions of the two [mutually saturated] phases or solutions [against their common vapour] ... [Pg.170]

Antonoff s rule agrees with the result that the interfacial tension 0 12 is less than the larger (ori) of the two surface tensions, arid it requires that when two partly miscible liquids are in equilibrium the spreading coefficient (contact angle. The value of (7i2 decreases with rise of temperature. [Pg.170]


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See also in sourсe #XX -- [ Pg.39 , Pg.41 ]




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Interfacial tension

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