Polyelectrolytes Coulomb Interaction

Though the theory of Derjaguin-Landau-Verwey-Overbeek (DLVO) [17, 18] was essentially designed for hydrophobic colloids, it is often applied to the analysis of the stability of polyelectrolyte solutions. According to this approach an overlap of the electrical double-layers of two charge-like colloidal spheres in an electrolyte solution always yields a repulsive screened Coulomb interaction, and the van der Waals forces are responsible for the attraction. A number of experiments in the recent decades, however, provide evidence that the effective interparticle potential shows a long-range attraction which cannot be ascribed to the van der Waals forces [15, 88-93], In spite of numerous theoretical attempts to explain this phenomena (for a review see [7, 8, 10, 94,... 

Theoretical considerations of the coulombic interactions of dissolved biopolymers have produced a complete picture of the distributions of counter and coions under the influence of the electrostatic charge on the macroion(56,57). The counterion condensation theory of Manning(56) has stimulated a great deal of activity in the study of dissolved macroions, especially because it provides a group of limiting laws describing the contribution of electrostatic effects to the thermodynamic and transport properties of polyelectrolyte solutions. Data... 

The collapse transition of polyelectrolyte macromolecules upon worsening of solvent quality was considered as a coil-globule transition of each of mflg blobs collapsed approximately as the chain of gif monomer units unperturbed by the Coulomb interaction [17]. It was shown that the collapse transition occurs somewhat below the 0-point. The corresponding relative temperature deviation... 

Protein purification by selective phase separation with anionic and cationic polyelectrolytes has been widely discussed by Dubin et al. [187]. The driving force of such a process is the intermolecular association with the participation of Coulomb interactions, hydrogen bonds and hydrophobic forces. Phase separation with polyampholytes has been described [188,189]. Due to the self-precipitation of polyampholytes at their own lEP in the absence of proteins, they can be used for protein extraction and purification. 

Structures formed by amphiphilic block copolymers composed of a hydrophilic block with ionic and, in particular, pH-sensitive (weak polyelectrolyte) segments, linked to a hydrophobic block, are more responsive. This is because the strength of repulsive Coulomb interactions between the polyelectrolyte (PE) segments can be efficiently tuned by variations in pH or/and ionic strength in the aqueous solution, while their thermoresponsive nature can be maintained if the hydrophobic block is well chosen. 

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