Electrolytes surfactant-polymer systems

Interfacial rheologic properties of different crude oil-water systems were determined in wide temperature and shear rate ranges and in the presence of inorganic electrolytes, surfactants, alkaline materials, and polymers [1056]. 

Gibbs monolayers are widespread. The simplest system is that of the surface of a fully miscible binary liquid. More complex ones are monolayers of uncharged molecules adsorbed from dilute solutions (example aliphatic alcohols from aqueous solution) electrolytes surfactants (non-ionic or ionic) polymers and polyelectrolytes and yet more. On the other hand, the methods for characterizing... 

Fundamental investigation of the system at the molecular level. This requires investigations of the structure of the solid/liquid interface, namely the structure of the electrical double layer (for charge-stabiUsed suspensions), adsorption of surfactants, polymers and polyelectrolytes and conformation of the adsorbed layers (e.g., the adsorbed layer thickness). It is important to know how each of these parameters changes with the conditions, such as temperature, solvency of the medium for the adsorbed layers, and the effect of addition of electrolytes. 

The initial polymer-surfactant-salt interaction studies prompted a question of the effect of addition order on the coacervation mechanism. If the salt is added first into a polymer environment will the coacervation phenomenon be the same as a system where surfactant and electrolyte are first introduced This question was addressed by investigating the effect of addition order in the presence of salt for both the synthetic and cellulosic polymer systems. The methods used for each system are discussed in the Experimental section and the addition orders are outlined in Table II. 

Figure 20.18. Effect of introducing charges in a mixture of a nonionic polymer and a nonionic surfactant, illustrated for the mixture of dextran and a polyoxyethylene surfactant (reference system in (a)). Both upon introducing a low fraction of ionic surfactant in the micelles (b) or a low amount of sulfate groups in dextran (c), the mutual miscibility is strongly enhanced. This can be eliminated either if electrolyte is added or if both the polymer molecules and the micelles are charged (d). Above the curves there is miscibility, while below there is phase separation into two solutions. The dashed curves give the miscibility limits for the reference system. (Redrawn from K. Bergfeldt and L. Piculell, J. Phys. Chem., 100 (1996) 5935)...

Uses Antisoiling agent, improves weatherability in paints, coatings, sealers coupling agent for fillers in performance polymer systems surfactant in oil field applications solubilizer for paraffins Features High electrolyte tolerance... 

Because the effective HLB of a given surfactant will depend on the nature of the solvent, HLB numbers cannot be considered to be absolute, reaUstic measures of the emulsifying ability of a material under all conditions. The actual HLB of a surfactant in a system will depend on the nature of the solvent, the temperature, and the presence of additives such as cosolvents, electrolytes, and polymers. Although the relationship will not always be linear, the HLB may be expected to vary in a manner analogous to that found for the critical micelle concentration of the surfactant under the same conditions. 

Owing to its chemically highly aggressive nature, fluorine is difficult and hazardous to handle and it can be manufactured only via the electrolytic oxidation of fluoride. Fluorine gas has been produced commercially since 1946 and has found applications in many areas of fluorine chemistry (polymers, surfactants, lubricants, thermally stable liquids, blood replacement and pharmaceuticals, propellants, etc.). Inorganic fluorides such as Sp6 and UFe [21] have technical applications. Fluorous solvent systems [22] provide novel reaction environments fundamentally different from both aqueous and hydrocarbon media [23] and fluorine has been employed as a marker or spin label [24]. 

The ccc values for a number of polymer latices have been determined and some typical values are reported in Table II. The trends observed are qualitatively in agreement with those expected from the theoretical approach for particles with smooth surfaces, with everywhere the same, using simple electrolytes, i.e., those which do not interact chemically with water to form new ionic species. These values should only be used for qualitative guidance since, in addition to the factors already mentioned, there can be variations of the ccc with particle size, type and density of surface groupings, and the presence or absence of stabilizing materials such as surfactants. In practice it is advisable to determine the actual value for a particular latex system. 

In the Current State of the Art we will review some of the recent SANS and reflectivity data from ISIS, which also serve to point to future directions and opportunities. Recent reflectivity measurements, on the adsorption of polymers and polymer/surfactant mixtures at interfaces, surface ordering in block copolymer systems, time dependent inter-diffusion at polymer-polymer interfaces, and the contribution of capillary waves to interfacial widths, will be described. The use of SANS to investigate the dynamic of trans-esterification of polyester blends, the deformation of copolymers with novel morphologies, and the use of diffraction techniques to determine the structure of polymeric electrolytes, will be presented. 

Gelatin is hydrolyzed by most of the proteolytic systems to yield amino components. Further, it reacts with acids and bases, aldehydes and aldehydic sugars, anionic and cationic polymers, electrolytes, metal ions, plasticizers, preservatives, and surfactants. Even, exposure to stress conditions of humidity, temperature, and/or light leads to perceptible changes. 

Poly(propylene oxide) is typically obtained by base catalyzed anionic polymerization of propylene oxide [12]. Both stereospecific and atactic forms are known. The polymer is used as a soft polyether unit in polyurethane elastomers and foams in polymer electrolytes as surfactants (lubricants, dispersants, antistatic agents, foam control agents) in printing inks, as solubilizers in hydraulic fluids, coolant compositions in various medical applications (protective bandages, drug delivery systems, organ preservation, dental compositions), etc. 

Enormous effort is spent on studying complex fluids, more-so than any of the previous topics reviewed above. These fluids include polymer solutions and melts, alkanes, colloidal systems, electrolytes, liquid crystals, micelles, surfactants, dendrimers and, increasingly, biological systems such as DNA and proteins in solution. There are therefore many specialist areas and it is impossible to review them all here. As such, we sample only a select few areas that reflect our own personal interests, and apologise to readers who have specific interests elsewhere. First, we briefly look over some simulations on colloidal systems, alkanes, dendrimers, biomolecular systems, etc, and will then... 

From a physical point of view, suspensions are usually unstable systems, as the solid phase almost always tends to form a sediment. One of the most important aims with this type of dosage form must therefore be to prevent sedimentation. As this ideal condition can usually not be achieved, it is at least attempted to reduce the sedimentation rate and, above all, to make any sediment easy to redisperse. A number of auxiliaries are used in pharmaceutical technology to achieve this. They include thickeners, hydrophilic polymers, sugars and sugar alcohols, surfactants and electrolytes [296]. In spite of its insolubility, crospovidone can be classed as a hydrophilic polymer. 

It is speculated that the effect of temperature on the critical electrolyte concentration is similarly related to the effect of temperature on the structure of aqueous solutions. An increase in temperature has been shown to extend the range of micellar solutions to a higher salinity in anionic surfactant systems (31). Hence, polymer-aggregate incompatibility would be less when the temperature is increased. However, addition of alcohol or change in temperature... 

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