Surface tension sodium chloride

Fig. III-9. Representative plots of surface tension versus composition, (a) Isooctane-n-dodecane at 30°C 1 linear, 2 ideal, with a = 48.6. Isooctane-benzene at 30°C 3 ideal, with a = 35.4, 4 ideal-like with empirical a of 112, 5 unsymmetrical, with ai = 136 and U2 = 45. Isooctane-

The thickness of the equivalent layer of pure water t on the surface of a 3Af sodium chloride solution is about 1 A. Calculate the surface tension of this solution assuming that the surface tension of salt solutions varies linearly with concentration. Neglect activity coefficient effects. 

An indirect estimate of surface tension may be obtained from the change in lattice parameters of small crystals such as magnesium oxide and sodium chloride owing to surface tensional compression [121] however, these may represent nonequilibrium surface stress rather than surface tension [68]. Surface stresses may produce wrinkling in harder materials [122]. 

Figures 12 and 13 show plots of the surface tension of sodium dodecyl ether (1 EO) sulfate and sodium dodecyl sulfate (2 EO) sulfate vs. their bulk concentration in distilled water and in sodium chloride solutions of 0.1 and 0.5 M total ionic strength at 10, 25, and 40°C [125].

Surfactant mixtures were used as obtained and are listed with their properties in Table II. Sodium chloride and calcium chloride were Fisher reagent grade. Deuterium oxide was Aldrich Gold Label and had a surface tension of 70.4 mN/m at 23°C measured with a W iI heImy pi ate tens i ometer. 

An important qualitative conclusion, which agrees with experience, can immediately be drawn from the theoretical considerations we have developed. A small quantity of dissolved substance may reduce the surface tension very considerably, but can only increase it slightly. Thus, sodium chloride increases the surface tension of water to a small extent the concentration in the surface layer is accordingly smaller than in the bulk and the effect of the solute is thus counteracted. On the other hand, many organic salts, e.g., the oleates, reduce the surface tension and therefore accumulate in the surface layer, so that, in extreme cases, the whole of the solute may be collected there and produce a considerable effect, although the absolute quantity may be exceedingly slight. 

Magnesium oxide crystals about 500 A. in diameter were prepared in vacuo by Nicolson 26). Lattice determinations by X-rays showed that the parameter of these small crystals was smaller than that of large crystals. The surface tension obtained from these experiments (- -3,020 dynes/cm.) was 46% of the theoretical value. Similar experiments were carried out with sodium chloride crystals made in vacuo (size about 2000 A), and the agreement between experiment and theory was better, the observed surface tension (- -390 dynes/cm.) being 70% of that calculated. 

Hematological effect. Decoction of the dried leaf, administered orally to adults at a dose of 3 mL/person, did not alter blood surface tension and viscosity. Infusion of the dried leaf, administered orally to adults at a dose of 5 mL/person, produced no change in the blood levels of sodium, potassium, and chloride " . 

Figure 4.11 Surface tension of aqueous sodium chloride solutions at 20°C...

Materials. Sodium dodecylsulfate (SDS) and fully deuterated sodium dodecylsulfate (SDS-d ) were obtained from Sigma and Cambridge Isotope Laboratories respectively, and used as received. The cationic surfactants, dodecyltrimethylammonium chloride (DTAC), dodecyltrimethylammonium bromide (DTAB), and didodecyldimethylammonium bromide (DDAB) were purchased from Eastman Kodak, and purified by repeated recrystallization from an ethanol/acetone solvent pair. Even so, a small amount of surface active impurity was observed in surface tension plots for DTAC. The tetradecyldimethylamine oxide (C14AO) was a commercial sample (Ammonyx MO) obtained from Stepan (Control No. 533-30027). This sample is primarily C14AO, but also contains other chain length components. Sodium chloride (NaCl) was obtained from EM Science and used as received. Water was purified by a three stage Bamstead water purification system. 

Films of the complexes are stable in water at a pH of 7 while they dissolve at pH 5. This can be explained by the pKa value of retinoic acid, which is, for example, 6.05 in 150 mM NaCl and 6.49 in 5 mM NaCl [163]. Therefore, the anionic retinoic moieties within the complexes will be protonated at pH values lower than the pKa which lead to the cleavage of the ionic bonds in the complexes. The first experiments to evaluate the release properties of retinoic acid from thin films of the complexes were performed by using FTIR and surface tension measurements. Films were immersed in solutions of 0.15 m sodium chloride at pH 5 for both methods. The increase of the absorbance at 1255 cm-1 (C-0 stretch vibration) [186] in the FTIR spectra was used as a qualitative measure for the release of retinoic acid from the PEI-retinoate complexes. For comparison, the spectra of the complex and of the non-com-plexed retinoic acid are shown at wave numbers around 1255 cm 1 (Fig. 26, insert curves a and b). The time-dependency of the absorbance, which is a relative measure of the amount of released retinoic acid, is shown in Fig. 26. It can be seen that the increase of the absorbance, and therefore the release... 

Fig. 27 The effect of the molecular weight of PEI retinoate complexes on the surface tension of 0.15 m/L sodium chloride solutions as a function of time. The samples are PEI-600 retinoate (diamonds), PEI-2000 retinoate (circles), PEI-25000 retinoate (squares) and PEI-750000 retinoate (triangles). Reprinted with permission from [179]. Copyright 2000 American Chemical Society...

One way to obtain ys from the measured difference ys — K.sv is described by Weiler et al.. who determined the surface tension of finely divided sodium chloride [88], They measured ys — ysv for ethanol and benzene up to saturating vapor pressure. Then they assumed that at saturating vapor pressure ysv is similar to the solid-liquid surface tension ysL- At saturating vapor pressure the surface of a solid is covered with a multilayer of the adsorbed vapor. Consequently the surface tension should not be significantly different from the solid-liquid interface. Taking ysL =171 mN/m from solubility experiments [204J and measuring ys - ysv = 56 mN/m for ethanol, they obtained ys = 227 mN/m. 

The capillary-rise method is used to study the change in surface tension as a function of concentration for aqueous solutions of />butanol and sodium chloride. The data are interpreted in terms of the surface concentration using the Gibbs isotherm. 

An appreciation of the properties of liquid electrolytes can be gained by a comparison between molten ice (water) and molten sodium chloride (Table 5.2). Both liquids are clear and colorless. Their viscosities, thermal conductivities, and surface tensions near their melting points are not very different. 

The surface tension of fused silica is only about three times that of fused sodium chloride. Hence [see Eq. (5.144)] in fused silica also there would be many holes of atomic dimensions, as for fused ionic liquids. 

Calculate the work of hole formation in molten sodium chloride, using the Furth approach. The surface tension of NaCl, molten salt at 1170 K, is 107.1 dyn cm" and the mean hole radius of NaCl is 1.7 x 10" cm. (Contractor)... 

Using the distribution function, make a plot of probability that a hole has a radius in molten sodium chloride at 1170 K. The surface tension of molten sodium... 

The simplest way of dyeing a fiber is by a direct dye. The dye is dissolved in water so that its concentration is about 0.02 to 0.1 per cent. The amount of dye depends on the weight of the cloth. For light shades the amount of dye is 0.05-0.3 per cent, and for deep shades 4-10 per cent, of the weight of the cloth. A small amount of sulfated alcohol soap is added to reduce the surface tension of the solution and thereby aid in the penetration of the dye. Inorganic salts are added to the dye bath, such as sodium chloride for cotton dyes and sodium sulfate for wool dyes, in amounts varying from 5 to 10 per cent. The fiber is steeped in the dye bath and heated at 80-100° until the proper shade has been... 

Will the surface tension of molten sodium chloride be higher than or lower than that of carbon tetrachloride Explain. 

CMCs of these polyfluorinated surfactants are of the order of 10 5 m.47 Plots of the observed H chemical shifts versus surfactant concentration of cetyl trimethyl ammonium chloride, cetyl pyridinium chloride, cetyl dimethyl phenyl ammonium chloride, cetyl dimethyl benzyl ammonium chloride, cetyl dimethy 1-2-phenyl ethyl ammonium chloride, and cetyl dimethyl-3-phenyl propyl ammonium chloride, are sigmoidal and were fitted to a model based on the mass action. The H chemical shift-based CMC values are in excellent agreement with those determined by the surface tension method.48 The micellization processes of dodecyl trimethyl ammonium halides (chloride and bromide) studied by calorimetric titration show different behaviors at 298 K. However, these disappear at 313 K, while the results measured by the chemical shift versus surfactant concentration do not show this difference.49 The CMC of 3-aminopropyl triethoxy silane in toluene is ca. 0.47m, measured by H and l3C chemical shifts.50 The CMC of optically active potassium A -n-dodecanoyl alaminate measured by H and l3C chemical shifts is lower (11-15 him) in D20 than that in a mixed solvent of 1,4-dioxane and D20 (19mM).-51 The H chemical shift shows that the CMC of resorcinol-type calix[4] phosphoric esters having four alkyl side-chains, [4]Ar 5P-R-n, is insensitive to the length of the side-chains, n.52 The CMC values of a family of surfactants, the sodium cyclohexyl alkanoates, with different lengths of the alkanoate side-chains, were obtained from 13C chemical-shift measurements. The results show that these amphiphiles have high CMCs (0.12-1.02 m).-53... 

Surface tensions of aqueous solutions of inorganic electrolytes are well known to be larger than the surface tension of pure water at the same temperature. The surface tension of 2 M (10.5 mass%) sodium chloride solution is about 3.3 mN/m larger than the surface tension of... 

Figure 5 The effect of gelatin on the surface tension of sodium n-dodecyl-sulphate (SDS) in water and 0.2 M sodium chloride. SDS in water O, SDS in 0.5% gelatin > SDS in 0.2 M sodium chloride A, SDS in 0.5% gelatin, 0.2 M sodium chloride. (Reproduced from Knox and Parshall [52] with permission from Academic Press.)...

In fact, experimental surface tensions of mixtures of sodium decyl sulphate SDeS (component 1) and sodium dodecyl sulphate SDS (component 2) are described satisfactorily by Eq. (2.48) whereas the application of Eq. (2.51) leads to large differences between theory and experiment [67]. The best agreement between experimental and theoretical values of n was received by using the Frumkin analogue of Eqs. (2.48)-(2.50) with ai=0.7, a2=0.85 and ai2=(ai+a2)/2=0.77. Similarly, mixtures of decyl ammonium chloride and dodecyl ammonium chloride were very well described by these equations with ai=1.2, a2=1.56 and ai2=(ai+a2)/2=1.38 [16]. The latter system also reveals a reverse salting-out effect as an excess of inorganic counterions in the solution increases the adsorption activity of an ionic surfactant, by the same token such an excess in the surface decreases the adsorption activity. As a result, the effect of a second ionic surfactant with a common counterion on the surface pressure is smaller than it would have been according to the additivity rule for non-ionic surfactants expressed in Eq. (2.51). 

Other studies in 2000 by Drew et al. reported that it is very difficult to spin fibers of PANI complexed to sulfonated polystyrene (PANFSPS), even when solutions containing sodium chloride and dodecyl benzene sulfonic acid sodium salt were used to lower the surface tension and thereby enhance electrospinning [16,17]. However, PANFSPS nanofibers can be produced by adding a carrier polymer such as PEO, polyacrylonitrile, or polyurethane. Also reported was the use of electrostatically layered sulfonated polystyrene as a template for the surface polymerization of conjugated polymers in their conducting form. Enzymatic synthesis of PANI and a copolymer of pyrrole and PEDOT was done on electrospun nanofiber... 

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