Polyelectrolyte solutions

In adsorption studies from saline environments it is necessary to prepare the water-soluble polymer and peptized montmorillonite in fresh water at high concentrations and to add each to a saline solution. Polyelectrolytes will frequently not "yield" the same viscosity as when they are dissolved in fresh water. Montmorillonite will flocculate in saline solutions. With fresh water mixing of components, reproducible results are obtained in the saline studies. After component mixing, agitation of the slurry is maintained with gentle stirring via... 

In scenario (c) corresponding to semidilute solutions, polyelectrolyte chains interpenetrate. Under these circumstances, there are three kinds of screening. The electrostatic interaction, excluded volume interaction, and the hydro-dynamic interaction between any two segments of a labeled polyelectrolyte chain are all screened by interpenetrating chains. Each of these three interactions is associated with a screening length, namely, and These screening... 

In dilute aqueous solutions, polyelectrolyte block copolymers self-assemble into micelles consisting of a hydrophobic core and a polyelectrolyte shell. The study of their structural properties is expected to provide a basic understanding of the properties of dense polyelectrolyte layers, electro-steric stabilization mechanisms, and actuator functions based on variations in the electrostatic interactions. 

If an electric potential gradient is applied in the solution, polyelectrolyte molecules will move in the direction of the electrode of opposite charge. This is called electrophoresis. If the polyelectrolyte is immobilized, the solvent will move in the electric field, a process called electroosmosis. These principles are applied in several laboratory techniques but will not be discussed here. 

Sulfonium salt monomer, I, is obtained by reacting a,a -dichloro-/)-xylene with excess tetrahydrothiophene at 50°C in methanol for 20 h. The monomer is purified by precipitation in cooled acetone. A polymerization reaction to form the water-soluble precursor polymer, II, is effected in aqueous solution by reaction of the monomer with an equimolar quantity of sodium hydroxide at 0 C for I h under rigorous anaerobic conditions. The reaction is quenched by neutralization with HCI solution. Polyelectrolyte should be separated from the residual monomers and low-... 

Wang L, Bloomfield VA. Small-angle X-ray scattering of semidUute rodlike DNA solutions polyelectrolyte behavior. Macromolecules 1991 24 5791-5795. 

Once the war was over in 1945, Fuoss accepted the Sterling Chair in Chemistry at Yale. The team of Onsager, Kirkwood and Fuoss made Yale the premier theoretical chemistry department in the world at this time. The focus of his work at Yale was on electrolyte solutions, polyelectrolytes and the statistical mechanics of condensed phase systems. He was elected to the National Academy of Sciences in 1951. While his interests continued to evolve after this period in directions different than the community of polymer scientists, his contribution to the period of the consolidation of the basic paradigms was seminal. The unique phenomena associated with linear polyelectrolytes stimulated much theoretical activity, both in the time of Fuoss and afterward. It remains a challenging, but rewarding, topic today. 

The reference state for the chemical potential of the solvent (water) is the pure liquid, whereas for the solute (polyelectrolyte) it is a hypothetical one molal solution of the undissociated polyelectrolyte in water (wp = m° = I mol/ kg water)), where it experiences interactions with water molecules only, i.e., in that reference state the undissociated polyelectrolyte is infinitely diluted in water (mp= 0 in pure water). The difference between the chemical potential of the polyelectrolyte in the real solution p.p T, mp) and in its reference state is calculated in five steps ... 

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