Macroscopic counterion diffusion in solutions of cylindrical polyelectrolytes

Nilsson, Lars Göran; Nordenskioeld, Lars; Stilbs, Peter; Braunlin, William H.

doi:10.1021/j100261a045

Cited by 57 publications

(59 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For a constant local diffusion coefficient D(r) an inhomgeneous distribution C(r) gives rise to a lowering of D ~u. The obstruction effect discussed in the previous section gives an example of this mechanism, but it appears that it is also the basic mechanism for lowering the diffusion coefficient of monovalent ions in the presence of charged particles [31,34]. For systems with divalent ions the picture seems more complex [33,34].…”

Section: The Effect Of Specific Interactions On the Selfdiffusionmentioning

confidence: 95%

“…The obstruction effect discussed in the previous section gives an example of this mechanism, but it appears that it is also the basic mechanism for lowering the diffusion coefficient of monovalent ions in the presence of charged particles [31,34]. For systems with divalent ions the picture seems more complex [33,34]. In the other mechanism, which is often the most important one for solvent diffusion, the decrease in D ~ is generated by a low local value of D(r).…”

Section: The Effect Of Specific Interactions On the Selfdiffusionmentioning

confidence: 95%

“…It is clear that the cell model gives a good description of the electrostatic effects over a wide concentration range [25][26][27]. For charged colloidal systems the cell model has also been used to describe the self-diffusion of counterions [28][29][30][31][32][33][34]. In this paper we follow this latter tradition and argue that the cell model is very useful for describing the self-diffusion of small molecules in colloidal and locally heterogeneous systems in general [35,36].…”

Section: The Cell Modelmentioning

confidence: 99%

See 2 more Smart Citations

Self-diffusion of small molecules in colloidal systems

Jönsson¹,

Wennerström²,

Nilsson³

et al. 1986

Colloid & Polymer Sci

280

241

View full text Add to dashboard Cite

Abstract:The self-diffusion of small molecules in colloidal systems is calculated using the cell model to describe the effect of varying concentration of colloidal particles. The relevant boundary conditions are found using arguments from the thermodynamics of irreversible processes. From a general description of the self-diffusion in systems with spherically symmetrical particles we derive expressions for the concentration dependence of the effective self-diffusion coefficient De~t for several cases of practical importance. It is shown that when the molecule studied is strongly attracted to the particle a minimum in D ~ff is expected around volume fraction 4~ = 0.35. It is also shown that the often made distinction between free and bound molecules is often problematic and a more general description is proposed. The obstruction effect generated by the excluded volume is discussed both for spherical and spheroidal systems. It is pointed out that the often used formula due to Wang ((1954) J Amer Chem Soc 76:4755) is incorrect for self-diffusion and for the obstruction factor for spheres we obtain (1 + 0.5 ~)-1. This expresion is tested both by experiments on water diffusion in systems containing latex particles and through computer simulations and it is found valid over a wide concentration range. For prolate ellipsoids the obstruction factor is not greatly different from that for spheres, while for oblate aggregates the limking obstruction factor of 2/3 can be obtained at low concentrations. It is demonstrated that this effect can be used to distinguish between different aggregate shapes. It is also shown that the disorder present in a solution of colloidal particles leads to a decrease in the obstruction effect.

show abstract

Section: The Effect Of Specific Interactions On the Selfdiffusionmentioning

confidence: 95%

Section: The Effect Of Specific Interactions On the Selfdiffusionmentioning

confidence: 95%

Section: The Cell Modelmentioning

confidence: 99%

See 1 more Smart Citation

Self-diffusion of small molecules in colloidal systems

Jönsson¹,

Wennerström²,

Nilsson³

et al. 1986

Colloid & Polymer Sci

280

241

View full text Add to dashboard Cite

show abstract

“…[40,57,58] The self-diffusion coefficient can also be obtained within the PB mean field approximation, using the PB-Smoluchowski diffusion model. [59] A comparison of lithium counterion diffusion coefficients determined in BD simulations, in the PB-Smoluchowski model, and in the experiment was performed in Ref. [57].…”

Section: Brownian Dynamics Of Counterions Around Dnamentioning

confidence: 99%

Molecular Simulations of DNA Counterion Distributions

Lyubartsev¹

2004

Dekker Encyclopedia of Nanoscience and Nanotechnology, Second Edition - Six Volume Set (Print Version)

View full text Add to dashboard Cite

“…Our previous measurements lo were performed on DNA samples equilibrated at relative humidities ( rhs ) between 66 and 84%, corresponding to DNA-DNA helix axis distances between 18 and 22 A (which is close to contact between the DNA surfaces), while the present measurements have been made in the range [22][23][24][25][26][27][28][29][30][31][32][33][34][35] A. Thus, while the previous measurements were performed on samples with no aqueous phase between the DNA helices, we have now made measurements on samples containing a water phase with approximate distances of [2][3][4][5][6][7][8][9][10][11][12][13][14][15] A between the DNA surfaces. These systems should be more relevant as a model for ordered DNA in uiuo, where the interhelical distance usually is within the range considered in our experiment^.^^ Since there is a relatively large water phase, it is of interest to obtain information on the applicability of polyelectrolyte theories to these systems.…”

Section: Introductionmentioning

confidence: 99%

Li⁺ counterion self‐diffusion in ordered DNA

et al. 1994

View full text Add to dashboard Cite

SYNOPSISThe anisotropic self-diffusion coefficient of 7Li+ ( I = 3 / 2 ) counterions has been studied in hydrated, macroscopically oriented Li-( B )DNA fibers a t relatively high water contents, corresponding to approximate DNA-DNA helix axis distances of 22-35 A, using the pulsed field gradient nrnr spin-echo method. Self-diffusion coefficients parallel ( Dll ) and perpendicular (D,) to the DNA helix axis increase with increasing salt content and with increasing DNA-DNA helix axis distance. The observed anisotropy Dll/Dl decreases from 1.6 to 1.2 with the DNA-DNA separation increasing from 22 to 35 A in the salt-free sample. This result can be understood by the obstruction effect caused by the DNA molecules themselves.The values of the Li' self-diffusion coefficients in the most water-rich system with no added salt (corresponding to an approximate distance of 35 A between the DNA helix axes) were Dll -1.15 X lo-'' m2 5-l and DL -0.98 X 10-l' m2 s -' , compared to 9.14 X lo-'' m2 s-l for the diffusion of Li+ in an aqueous solution of LiCl ( -2.1M). The possible occurrence of restriction effects in the DNA fibers have also been studied by determining the self-diffusion coefficient at different effective diffusion times. The self-diffusion coefficient of Li' in the sample with the largest DNA-DNA helix axis distance seems to be independent of the effective diffusion time, which indicates that the lithium ions are not trapped within impermeable barriers. The possibility of diffusion through permeable barriers has also been investigated, and is discussed. 0 1994 John Wiley & Sons, Inc. INTRODUCTIONDouble-helical DNA in aqueous solution is a highly charged polyelectrolyte and will therefore interact strongly with the neutralizing counterions and any added salt. These long-range electrostatic forces gives rise to considerable salt effects on many physical properties of DNA in solution.' Ion-DNA interactions have been extensively studied by quadrupolar ion nmr in dilute or semidilute isotropic solution~.'-~ These experiments can often be successfully interpreted by polyelectrolyte theory based on the Poisson-Boltzmann ( PB ) cylindrical cell model or the simpler counterion condensation theory.' Of special interest in the present context is a study3 where the counterion self-diffusion of Li+ in aqueous solutions of Li-DNA/ LiCl was measured Biopolymers, Vol. 34, 1605-1614 (1994) with the nmr method and found to be well described by a diffusion model based on the cylindrical PB equation.Naturally occurring DNA is most often arranged in a closely packed and ordered form, as e.g., in chromosomes, sperm heads, virus capsids, and bacterial nucleoids.6 This fact makes it interesting to study the counterion-DNA interactions in ordered DNA. After the pioneering work of Edzes et al.,7 a number of publications, where nmr studies of the counterions in oriented DNA are discussed, have been p~blished.~-'~ Among these, a previous study from this laboratory10 where the self-diffusion of Li' was studied in fibers of oriented B-DNA ...

show abstract

Macroscopic counterion diffusion in solutions of cylindrical polyelectrolytes

Cited by 57 publications

References 4 publications

Self-diffusion of small molecules in colloidal systems

Self-diffusion of small molecules in colloidal systems

Molecular Simulations of DNA Counterion Distributions

Li⁺ counterion self‐diffusion in ordered DNA

Contact Info

Product

Resources

About

Macroscopic counterion diffusion in solutions of cylindrical polyelectrolytes

Cited by 57 publications

References 4 publications

Self-diffusion of small molecules in colloidal systems

Self-diffusion of small molecules in colloidal systems

Molecular Simulations of DNA Counterion Distributions

Li+ counterion self‐diffusion in ordered DNA

Contact Info

Product

Resources

About

Li⁺ counterion self‐diffusion in ordered DNA