Limiting-laws of polyelectrolyte solutions. Ionic distribution in mixed-valency counterions systems. I: The model

Paoletti, Sergio; Benegas, Julio; Cesàro, Attilio; Manzini, Giorgio; Fogolari, Federico; Crescenzi, V.

doi:10.1016/0301-4622(91)87211-m

Cited by 39 publications

(70 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…R is the gas constant and n p the number of moles of polymer charged groups. Notice that equation (4) implies that selectivity is not associated with any specific binding site. Furthermore it is effective only in the condensation regime (i. e., for r A 0).…”

Section: Theorymentioning

confidence: 98%

“…In a previous publication 4) (to which we refer for full details of the theory) we have shown that the condensed fractions of both species of counterions and the functional form of the condensation volume V p can be obtained by minimising the total ionic free energy:…”

Section: Theorymentioning

confidence: 99%

“…Furthermore it is effective only in the condensation regime (i. e., for r A 0). In order to obtain the equilibrium values of the fractions of condensed counterions, as well as the functional form of the condensation volume V p , the usual minimisation of the total free energy, in the limit of infinite dilution, should be performed 1,4) .…”

Section: Theorymentioning

confidence: 99%

“…The aim of this note is to extend the polyelectrolytic model presented by Paoletti et al 4) for mixed counterion systems to include in a simple manner specific (albeit non-chemical bonding) interactions between a linear polyelectrolyte and a mixture of counterions of equal or different valence. The effect of the affinity interactions addressed here results in shifting the equilibrium of the distribution of free and condensed counterions of both species.…”

Section: Introductionmentioning

confidence: 98%

“…Nevertheless, when two or more counterion species of the same or different valence are present in solution, several experiments, including ours 12,14,17) , have shown that specific interactions, that depend on the polyion/counterion pair, modulate the electrostatic behaviour 6,10,13,14) resulting in a measurable counterion selectivity. The nature of these specific interactions has been attributed sometimes to counterion size, its matching with the polyion shape 3,6) , differences in (partial) dehydration energy upon condensation 3,11,16) or to other effects that may happen in the complicated local solvent in the immediate vicinity of the polyelectrolyte 4,9) . Thus, affinity is considered here as a measure of the difference of the average interactions of the condensed counterions with their surrounding in the condensation volume, as compared with their interactions within the bulk solvent.…”

Section: Introductionmentioning

confidence: 98%

See 4 more Smart Citations

Affinity interactions in counterion-polyelectrolyte systems: Competition between different counterions

Benegas¹,

Paoletti

Hoop

1999

Macromol. Theory Simul.

Self Cite

View full text Add to dashboard Cite

SUMMARY: Non-bonding, specific interactions between linear polyelectrolytes and different species of counterions (of equal or different valence) are considered in the framework of the counterion condensation theory. It is assumed that these interactions are of short distance nature and that, within our theoretical approach, they apply only to the counterions territorially associated (condensed) to the polyion, which are free to move within the condensation volume V p around it. It is found that a simple additive term in the total free energy is sufficient to account for this interaction, resulting in a modulation of the polyelectrolytically determined population of territorially bound counterions. The distribution of free and condensed counterions as well as its variation with the physicochemical variables of the solution can be readily calculated. Analysis of literature data on titrations of poly(methacrylic acid) and dextran sulfate in aqueous solution with different species of monovalent and divalent counterions show that both polyanions appear to have a modest affinity free energy (of about RT) for Ca ++ counterions when compared with Na + . On the other hand, polyion interactions with the Mg ++ /Na + pair are well described by bare polyelectrolytic interactions.

show abstract

Section: Theorymentioning

confidence: 98%

Section: Theorymentioning

confidence: 99%

Section: Theorymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 98%

See 3 more Smart Citations

Affinity interactions in counterion-polyelectrolyte systems: Competition between different counterions

Benegas¹,

Paoletti

Hoop

1999

Macromol. Theory Simul.

Self Cite

View full text Add to dashboard Cite

show abstract

Conformational stability of biological polyelectrolytes: Evaluation of enthalpy and entropy changes of conformational transitions

et al. 1998

View full text Add to dashboard Cite

A new method is proposed for the determination of the enthalpy and entropy changes of nonionic origin upon conformational transition of linear biopolyelectrolytes in solution. For all transition midpoints, defined by given temperature and ionic strength, the total free energy change of the system is zero, which means that the nonionic contribution to the free energy change is equal in value and opposite in sign to the polyelectrolytic one. The counterion condensation theory of linear polyelectrolytes provides for the appropriate analytical expression to be used in such calculations. Linear plots of the proper functions of the calculated free energy changes vs the proper functions of temperature allows for the determination of the enthalpic and entropic terms of the nonionic free energy change of transition. The method has been applied to the extensive available data of the ion‐induced conformational change of κ‐carrageenan, a linear sulfated galactan extracted from seaweeds. The method has proved very successful, with the results showing a remarkable convergency of the enthalpy values for different monovalent counterions. On the other hand, the above approach has made it possible to explain the known effect of counterion specificity on the transition by a small difference in the nonionic entropic contributions. © 1998 John Wiley & Sons, Inc. Biopoly 45: 203–216, 1998

show abstract

Thermodynamics of the conformational transition of biopolyelectrolytes: The case of specific affinity of counterions

et al. 1999

View full text Add to dashboard Cite

Limiting-laws of polyelectrolyte solutions. Ionic distribution in mixed-valency counterions systems. I: The model

Cited by 39 publications

References 12 publications

Affinity interactions in counterion-polyelectrolyte systems: Competition between different counterions

Affinity interactions in counterion-polyelectrolyte systems: Competition between different counterions

Conformational stability of biological polyelectrolytes: Evaluation of enthalpy and entropy changes of conformational transitions

Thermodynamics of the conformational transition of biopolyelectrolytes: The case of specific affinity of counterions

Contact Info

Product

Resources

About