Surfactant study

Surfactants Information on the pure and commercial grade surfactants studied with regard to structures, contaminations and activities is detailed in Table I. All surfactants were used as received. 

The Landau-Ginzburg model of a ternary mixture of oil, water, and surfactant studied here was proposed by Teubner and Strey [115] on the basis of the scattering peak in the microemulsion phase. Later it was refined by Gompper and Schick [116]. Its application to various bulk and surface phenomena is described in detail in Ref. 117. 

Table 2 Lift-off areas per molecule for different chiral surfactants studied at 25°C on a pure water subphase.

Phase separation in polyion complexed mixed monolayers containing HC cationic and anionic surfactants and a FC anionic surfactant studied by SPMs and SIMS... 

E. Forgacs, T. Cserhati, O. Farkas, A. Eckhardt, I. Miksik and Z. Deyl, Interaction between cholesterol and non-ionic surfactants studied by thin-layer chromatography. J. Liq. Chrom. Relat. Technol. 27 (2004) 1981-1992. 

Sancho-Chust, V., Bengochea, M., Fabra-Campos, S., Casabo, V.G., Martinez-Camara, M.J., and Martin-Villodre, A., Experimental studies on the influence of surfactants on intestinal absorption of drugs. Cefadroxil as model drug and sodium lauryl sulfate as model surfactant studies in rat duodenum, Arzneim.-Forsch./Drug Res., 45, 1013, 1995. 

P.M. Claesson, M. Bergstrom, A. Dedinaite, M. Kjellin, J.E. Legrand, and I. GriUo Mixtures of Cationic Polyelectrolyte and Anionic Surfactant Studied with Small Angle Neutron Scattering. J. Phys. Chem. B 104, 11689 (2000). 

The CMC can be determined using ultrafiltration (18). Figure 1 shows the CMC of NPEj g 3S a function of temperature and the thermodynamic properties determined using these data are given in Table I together with those of the other surfactants studied. The values are subject to some uncertainty because the complex CMC/temperature behavior renders differentiation of the data inaccurate. The values are, however, comparable to those for similar surfactants reported by others. 

Vasilescu, M., Angelescu, D., Almgren, M., Valstar, A. (1999). Interactions of globular proteins with surfactants studied with fluorescence probe methods. Langmuir, 15, 2635-2643. 

Malyusov ei al. (M6), 1955 in very short wetted-wall columns (no rippling) (3) flowing over spheres. Entry and end effects studied, also effects of adding surfactant. Study of distillation in wetted-wall columns, taking into account the effects of laminar and turbulent flow of vapor phase. 

Howkins and Davidson (H20), 1958 Investigation of stability of liquid film flowing over spheres in an upward airstream. Effects of surfactants studied. 

A number of recent studies focused on GI delivery of challenging molecules using nano-and microparticulate solid adsorbents in the presence of nonionic surfactants [75,76]. Since some nonionic surfactants studied to improve intestinal absorption are liquids or administered as aqueous systems, the presence of an adsorbent permits formulating them within a common solid dosage form, a tablet, whereas reducing the risk of drug degradation... 

ANIONIC SURFACTANTS STUDIED IN VINYL ACRYLIC LATEXES 07)... 

The Monomer-to-Micelle Transition. Surfactants having relatively high cmcs facilitate FT-IR investigations of the monomer to micelle transition, since monomer solutions can be prepared at concentrations that readily provide acceptable signal/noise ratios. However, if the cmc is too high, it is not always possible to prepare concentrated, isotropic micellar solutions for comparison with those of the monomer. Of the amine oxide surfactants studied here, C AO is the best choice for examining this transition since its cmc (0.11 M to 0.15 M) is in an appropriate range. 

With the increase in surfactant concentration pH first decreases, then reaches a constant value, equal to 3.4. The curve pH (C) for the both surfactants studied reaches a plateau at different concentrations, corresponding to the concentration Cbi of black spot formation (see Section 3.4.3). This concentration for non-ionic surfactants is close to that necessary to saturate the adsorption layer. At C > Cbt the isoelectric points found for 6-... 

At higher EO levels, the foam volume produced by AEGS and AESo surfactants were less adversely affected by the presence of an oil phase than were other surfactants studied (Table I. Figure 1). This behavior was likely due to the formation of an oil/water emulsion which stabilized the fluid films between gas bubbles. Although foam volumes were smaller, at 75°C in three different brines, the sensitivity of AE and AES surfactants to the presence of decane decreased with increasing surfactant ethylene oxide content. 

For most of the AES surfactants studied, the ratio of foam volume in the presence of added decane to that in its absence was relatively constant over the 0.5X-1.5X salinity range but decreased significantly when the solvent was 2.OX brine. 

A large package of data, and two well-con-trolled pivotal studies of safety and efficacy are rarely required, with the exception of diseases specific to childhood, such as surfactant studies in respiratory distress syndrome. This is especially the case if the drug has similar effects in both adult and pediatric populations, for example antihistamines. 

For the cationic surfactants studied, the excess molar refraction and solute hydrogen-bond acidity contribute positively to K although the effect is small. Solubilizate dipolarity exhibits a weakly negative contribution to and the solubilizate hydrogen-bond basicity a significant negative contribution to K. ... 

The synergisms of mixtures of anionic-cationic surfactant systems can be used to form middle-phase micro emulsions without adding short-chain alcohols [109, 110]. The surfactants studied were sodium dihexyl sulphosuccinate and benzethonium chloride. The amount of sodium chloride required for the middle-phase microemulsion decreased dramatically as an equimolar anionic-cationic surfactant mixture was approached. Under optimum middle-phase microemulsion conditions, mixed anionic-cationic surfactant systems solubilised more oil than the anionic surfactant alone. Upadhyaya et al. [109] proposed a model for the interaction of branched-tail surfactants (Fig. 8.16). According to this model the anionic-cationic pair allows oil to penetrate between surfactant tails and increases the oil solubilisation capacity of the surfactant aggregate. Detergency studies were conducted to test the capacity of these mixed surfactant systems to remove oil from... 

The premicellar region for the three surfactants studied showed a steeper slope than the expected 1 1 electrolyte slope. A possible explanation of this slope by the existence of a dimer in solution has been previously discussed (1). Additional work in this area is required. 

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