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Experimental results of measurements of refractive index and light scattering yield interesting information about the structure of the L2-phase. In accordance with previously presented studies they show that one, with respect to the role of water, has two main regions, one extending from the water-free phase up to a content of water of about 40% and the other at water contents above about 55%. An...
A review is presented about research on surface forces and surface interactions conducted over the past half-century, with some emphasis on the pioneering contributions of the Department of Surface Phenomena at the Institute of Physical Chemistry of the USSR Academy of Sciences.
The electrostatic contribution to the force across the apolar region in a lamellar liquid crystal is considered. For an ionic surfactant consisting of one small hydrophilic ion and one larger hydrophobic ion, a microscopic charge separation occurs. If the hydrophobic ion has a finite solubility in the apolar region a double layer force will be generated across the apolar region. It is shown that under...
Employing the theoretical approach and computational methods described previously [9], calculations have been made on the two-dimensional size/composition distribution of spherical micelles composed of sodium dodecylsulphate (SDS) and dodecylalcohol (DOH) monomers. These calculations show fair agreement with experimental CMC and solubilization capacity results. For rod-shaped micelles our calculations...
Results from direct force measurements between mica surfaces and modified mica surfaces immersed in aqueous electrolyte solutions are reported. In particular, experimentally observed attractive and repulsive deviations from force curves, calculated from conventional DLVO theory, are discussed. Such “additional” forces are present in most systems. Even in cases where the measured interaction appears...
Triplet energy transfer from 9-methylanthracene to azulene or guajazulene has been used to probe the migration of azulenes between micelles in aqueous solution. The migration of the hydrophobic solutes between small ionic and nonionic micelles had the temperature dependence expected for a process controlled by diffusion through the intermicellar solution, although the rate in some cases was substantially...
When a liquid containing surface active molecules advances on a hydrophilic solid surface, specific instabilities are observed. They are due to the diffusion of the surface active molecules which adsorb on the surface, increasing the contact angle. These instabilities appear as waves travelling along the contact line and are visible only in a limited range of liquid edge velocities.
The rate of spreading of non-volatile liquids on smooth and on rough surfaces was investigated. The radius of the wetted spot was found to agree with recently proposed scaling laws (t1/10 for capillarity driven and t1/8 for gravity driven spreading) when the surface was smooth. However, the crossover between these regimes was not observed at a constant value of the radius. Rough...
The thermodynamic properties of an inhomogenous fluid confined to a narrow slit with attractive walls have been studied using a simple mean field theoretical approach. The pair-wise interaction assumed is a truncated Lennard-Jones potential with a repulsive hard core. Density profiles of the fluid in the slit, the excess grand potential per unit surface area and the pressure tensor components...
Precipitation processes, solubility and phase behaviour in aqueous solutions of ferric nitrate—dodecyl benzene sulphonic acid (HDBS)—nitric acid, were investigated in various pH regions. Precipitation diagrams were made using light scattering. The solubility product and the enthalpies of precipitation were calculated taking into account the hydrolytic constants of Fe+3, Fe(OH)+2, Fe(OH)2 ...
Electromotive force and conductivity measurements have been used to study the counter ion association to micelles of sodium dodecyl sulfate, sodium dodecanoate, and sodium octanoate. The conductivity and electromotive force measurements match very well as both is mainly a measure of the amount of free counter ions in the solutions. Addition of alcohols to these micellar solutions show some differences...
Microemulsions based on aliphatic hydrocarbon, surfactant and aqueous buffer have been used as reaction medium for the lipase catalyzed transesterification of a triglyceride and a fatty acid. Both AOT (sodium bis (2-ethylhexyl)sulfosuccinate) and certain alcohol ethoxylates could be used as surfactant to produce a triglyceride having a fatty acid composition similar to that of natural cocoa butter...
A surface wettability gradient method for the investigation of some quantitative aspects of protein adsorption on solid surfaces has been developed. The method has been used in studies of protein exchange reactions on silicon surfaces. The proteins used were human fibrinogen and γ-globulin and specific detection of these proteins was made using corresponding antibodies. By the gradient method, the...
Binary and ternary phase diagrams have been determined for systems containing sodium di-2-ethylhexylsulfosuccinate (Aerosol OT); a polar solvent, formamide, methylformamide, dimethylformamide or ethanediol; with and without hydrocarbon, toluene or dodecane. In formamide, Aerosol OT forms a lamellar, a viscous isotropic (cubic) and a reverse hexagonal liquid crystalline phase. The swelling of the lamellar...
A hydrophilic, non-ionic surface was prepared by grafting polyethyleneoxide (PEO) onto polyethylene (PE) and mica substrates. Monofunctional PEO-aldehyde was coupled by means of reductive amination to primary and secondary amino groups of polyethyleneimine (PEI) adsorbed on oxidized polyethylene (PE) and on mica. Optimum values of the reaction parameters influencing the reductive amination in this...
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