Solute-surfactant

Surfactant values are at the critical micelle concentration (CMC) in aqueous solution surfactant/defoamer values are at 0.1% concentration in aqueous solution. 

Organized Solutions Surfactants in Science and Technology, edited by Stig E. Friberg and Bjorn Lindman... 

Anionic Surfactants Biochemistry, Toxicology, Dermatology. Second Edition, Revised and Expanded, edited by Christian Gioxhuber and Kiaus Kunstier Organized Solutions Surfactants in Science and Technology, edited by Stig E. Friberg and Bjorn Lindman... 

Surfactant, total Surfactant, solution Surfactant, interfacial layer H2O 1 H20 rev.mic. 

Bilayer lipid membranes (BLMs) 2D, 3D 30- to 50- Painting of the surfactant (or A-thick, 1- to 2- lipid), dissolved in a hydrocarbon mm-diameter mem- solvent, across a teflon pinhole brane, supported which separates two by a solvent compartments of aqueous solution surfactant reservoir the Plateau-Gibbs border or torus) and separating two aqueous solutions macroscopically Hours Convenient system for fundamental studies as simultaneous electrical and spectroscopic measurements were possible 385, 387... 

Figure 3. Density modification of chlorobenzene with surfactant/n-butanol solutions. Surfactant (A) SN120, (B) Brij 35, (C) Tween 80.

The equilibrium solution surfactant concentration needed to achieve a specified level of adsorption at an interface. Example one such measure of efficiency is the surfactant concentration needed to reduce the surface or interfacial tension by 20 mN/m from the value of the pure solvent(s). This term has a different meaning from surfactant effectiveness. 

If the surface or interfacial tension is reduced with the addition of a solute (surfactant), V is positive (concentration of the solute at the solution surface is higher than that in the bulk liquid). If the surface tension is elevated with the addition of a solute (such as K2C03), F is negative (concentration of the solute at the solution surface is lower than that in the bulk liquid). 

In dilute aqueous solutions, surfactants have normal electrolyte or solute characteristics and are formed at the interface. As the surfactant concentration increases beyond the well-defined concentrations (i.e., critical micelle concentration, c.m.c.), the surfactant molecules become more organized aggregates and form micelles. At the c.m.c., the physicochemical characteristics of the system (osmotic pressure, turbidity, surface tension, and electrical conductivity) are suddenly changed, as shown in Figure 4.19. 

Structure Formation in Surfactant Solutions. Surfactants, also referred to as soaps, detergents, tensides, or surface active agents, are amphiphilic molecules possessing both hydrophilic and hydrophobic regions. They can be classified as anionic, cationic, zwitterionic, or nonionic (neutral) depending upon the nature of the polar... 

In our laboratories, extensive use has been made of vapor pressure (14-18) and membrane methods ( 2, 3, 19, 20) to Infer thermodynamic results for ternary aqueous systems containing an ionic or a nonionic surfactant and an organic solute. The most precise solubilization measurements ever reported have been obtained with an automated vapor pressure apparatus for volatile hydrocarbon solutes such as cyclohexane and benzene, dissolved In aqueous solutions of sodium octylsulfate and other Ionic surfactants (15, 16). A manual vapor pressure apparatus has been employed to obtain somewhat less precise results for solutes of lower volatility (17, 18). Recently, semi-equilibrium dialysis (19, 20) and MEUF (2) methods have been used to investigate solute-surfactant systems in which the organic solubilizates are too involatile to study by ordinary vapor pressure methods. 

As we know, the surface tension of water is high. When droplets of water fall on waxy surfaces, they tend to form small spheres. If a surfactant is added to water, surfactant molecules will displace some water molecules from the surface, which lowers the surface tension (Figure 2.7). As a result, the droplets can spread over the waxy surface and lose their spherical shape. Therefore, in addition to acting as surface-active agents in spray solutions, surfactants also lower the surface tension of water, thus increasing the area of contact. 

G. KarlstrOm and B. Lindman, in Organized Solutions Surfactants in Science and Technolc y, edited by S. E. Friberg and B. Lindman, pp 49-66 (Marcel Dekker, New York, 1992). 

For dilute solutions, surfactant activity equals concentration, and F is calculated from the plot of 7 versus molar concentration. 

Shinoda, K., ed.. Solvent Properties of Surfactant Solutions, Surfactant Science Series, Vol 2, Marcel Dekker, New York, 1967. 

However, surfactants incorporated into the electrolyte solution at concentrations below their critical micelle concentration (CMC) may act as hydrophobic selectors to modulate the electrophoretic selectivity of hydrophobic peptides and proteins. The binding of ionic or zwitterionic surfactant molecules to peptides and proteins alters both the hydrodynamic (Stokes) radius and the effective charges of these analytes. This causes a variation in the electrophoretic mobility, which is directly proportional to the effective charge and inversely proportional to the Stokes radius. Variations of the charge-to-hydrodynamic radius ratios are also induced by the binding of nonionic surfactants to peptide or protein molecules. The binding of the surfactant molecules to peptides and proteins may vary with the surfactant species and its concentration, and it is influenced by the experimental conditions such as pH, ionic strength, and temperature of the electrolyte solution. Surfactants may bind to samples, either to the... 

The concentration fluctuations in our system can possibly further be subdivided into a solute (surfactant aggregates) concentration fluctuation and a solvent concentration fluctuation. The solute concentration fluctuation is similar to that of critical-like behavior observed in many W/0 microemulsion systems (28), while the solvent... 

Mittal, K. L., and D. O. Shah. Adsorption and Aggregation of Surfactants in Solution. Surfactant Science Series, vol. 109. New York Marcel Dekker, 2003. 

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