Poly electrolyte effect

For charged surfaces, complex stability may be enhanced (or reduced) by the poly electrolytic effect, if the pH is significantly different from the pH of zero charge, pHpzc, of the surface [106,146], In that case, the equilibrium constant, K, between the solute and a surface site, S, can be expressed as ... 

Mattison K. W., Dubin P. L., Brittain I. J. complex formation between bovine serum albumin and strong poly electrolytes effect of polymer charge density. J. Phys. Chem. B 1998 102 3830-3836. 

In semidilute solution and upon addition of salt (NaCl) an anti-poly-electrolyte effect was observed. That means that the viscosity ifacreased with the ionic strength and was several orders of magnitude higher than that measured in pure water [8-9]. 

Chen FG, Liu GM, Zhang GZ (2012) Formation of multilayers by star poly electrolytes effect of number of arms on chain interpenetration. J Phys Chem B 116 10941-10950... 

The polyelectrolyte catalysis of chemical reactions involving ionic species has been the subject of extensive investigations since the pioneering studies of Morawetz et al. [12] and Ise et al. [13-17]. The catalytic effect or the ability of poly-electrolytes to enhance or retard reaction rates is mainly due to concentration or exclusion of either or both of the ionic reactants by the polyions added to the reaction systems. For example, the chemical reaction between ionic species carrying the same charge is enhanced in the presence of polyions carrying the opposite charge. This enhancement can be attributed to an increase in the local concentration... 

For poly electrolyte solutions with added salt, prior experimental studies found that the intrinsic viscosity decreases with increasing salt concentration. This can be explained by the tertiary electroviscous effect. As more salts are added, the intrachain electrostatic repulsion is weakened by the stronger screening effect of small ions. As a result, the polyelectrolytes are more compact and flexible, leading to a smaller resistance to fluid flow and thus a lower viscosity. For a wormlike-chain model by incorporating the tertiary effect on the chain... 

Electrolyte Effect on Polymer Solution Rheology. As salt concentration in an aqueous poly(1-amidoethylene) solution increases, the resulting brine becomes a more Theta-solvent for the polymer and the polymer coil compresses(47) This effect is particularly pronounced for partially hydrolyzed poly(l-amidoethylene). The... 

E.V. Kudryashova, A.K. Gladilin, A.V. Vakurov, F. Heitz, A.V. Levashov, and V.V. Mozhaev, Enzyme-poly electrolyte complexes in water-ethanol mixtures negatively charged groups artificially introduced into alpha-chymotrypsin provide additional activation and stabilization effects. Biotechnol. Bioeng. 55, 267-277 (1997). 

In obtaining Eqs. (217)-(219), we have employed the preaveraging approximation and assumed that solvent motion is instantaneous in comparison to the motion of poly electrolytes. For a solution of polyelectrolytes, the effective medium theory for the equilibrium properties gives... 

As discussed extensively in this chapter, most of the surprising properties of polyelectrolyte dynamics are due to the coupling of counterion dynamics with polymer dynamics. But, there is no adequate understanding of how much of the counterions are mobile and how much are effectively condensed on polymer chain backbone. Theoretical attempts [77, 78] on counterion condensation need to be extended to concentrated poly electrolyte solutions. 

The effective dielectric function of poly electrolyte solutions remains as a mystery, demanding a better understanding of structure of solvent surrounding poly electrolyte molecules. 

Polyelectrolytes are most commonly studied as solutions in aqueous media as a consequence of their poor solubility in organic solvents. In order to minimize the effects of ionization in an aqueous media, evaluation of [77] is done in an aqueous solution of an inert 1 1 electrolyte as the solvent. In such solvents, poly electrolytes behave as if they were neutral polymers [32-34],... 

The suggested rod like structure of the pendant-type FVP-Co(III) complex is supported by the viscosity behavior of the polymer-complex solution (Fig. 3)2 The PVP-Co(III) complexes have higher viscosity than PVP this suggests that the polymer complex has a linear structure and that intra-polymer chelation does not occur. The dependence of the reduced viscosity on dilution and the effect of ionic strength further show that Co(en)2(PVP)Cl] Cl2 is a poly(electrolyte). The polymer complexes with higher x values have a rodlike structure due to electrostatic repulsion or the steric bulkiness of the Co(III) chelate. On the other hand, the solubility and solution behavior of the polymer complex with a lower x value is similar to that of the polymer ligand itself. 

The term tertiary electroviscous effect is applied to the changes in the conformation of poly electrolytes that are caused by //t/ramolecular double-layer interactions. It is customary to extend this definition to include all effects in which the geometry of the system is altered as a result of double-layer interactions. 

When photoinduced electron transfer produces products of opposite charge, their physical separation will be enhanced by the presence of a charged poly-electrolyte, with the quantum yield for electron transfer increasing from zero to one in a particular dramatic example [159]. Similar effects will cause inhibition of back electron transfer as well, although the magnitude of these effects is often much smaller than in the photodriven reactions. 

Residual silanol groups are present on the surface, which may have a negative effect on the peak shape of basic solutes and poly-electrolytes in particular. 

In order to describe the effect of ionic strength and pH, the electrost itic energies resulting from the oligoelectrolytic character of humic and fulvic acids (i.e., intermediate in character between simple ions and true poly electrolytes) must be assessed. The polyelectrolytic and oligoelectrolytic effect in proton and metal-ion binding has been well studied in physical biochemistry. 

Figure 9.33. (a) Schematic description of the effects of ionic strength (I) and pH on the conformations of a humic molecule in solution and at a surface. Rh denotes the hydrodynamic radius of the molecule in solution and 6h denotes the hydrodynamic thickness of the adsorbed anionic poly electrolyte. (Adapted from Yokoyama et al., 1989 and O Melia, 1991). (b) The influence of ionic strength of pH on diffusion coefficient, Dl, and on Stokes-Einstein radius of a humic acid fraction of 50,000-100,000 Dalton. (From Cornel et al., 1986). 

For both PAA and HA, the lability of rare earth element interactions is greater for the smaller molecular weight fractions of each poly electrolyte. Similar observations have been reported for Cu(II) dissociation from size fractionated HA (22). Interestingly, the smaller size fractions of HA have been shown to the most effective in transporting Am(III) and Cm(III) through sandy aquifers (25). Consequently, the influence and affect of polyelectrolyte size must be considered when predicting the mobility of these complexes in natural systems. 

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