Neutron Scattering Studies of the Structure of a Polyelectrolyte Globule in a Water−Acetone Mixture

Aseyev, Vladimir; Klenin, S.I.; Tenhu, Heikki; Grillo, Isabelle; Geissler, Erik

doi:10.1021/ma0016331

Cited by 61 publications

(71 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As pointed out by Jeon and Dobrynin [39], with the increase of the polyion concentration, counterions condense inside beads of the necklace globule, favoring the reduction of its charge and the increase of its mass which further promote the counterion condensation giving rise to the avalanche-like process. The necklace conformation is supported by experiments [40] and computer simulations [41,42].…”

Section: Poor Solvent Conditionmentioning

confidence: 82%

Does Electrical Conductivity of Linear Polyelectrolytes in Aqueous Solutions Follow the Dynamic Scaling Laws? A Critical Review and a Summary of the Key Relations

Cametti

2014

Polymers

View full text Add to dashboard Cite

Abstract:In this review, we focus on the electrical conductivity of aqueous polyelectrolyte solutions in the light of the dynamic scaling laws, recently proposed by Dobrynin and Rubinstein, to take into account the polymer conformations in different concentration regimes, both in good and poor solvent conditions. This approach allows us to separate contributions due to polymer conformation from those due to the ionic character of the chain, and offers the possibility to extend the validity of the Manning conductivity model to dilute and semidilute regimes. The electrical conductivity in the light of the scaling approach compares reasonably well with the observed values for different polyelectrolytes in aqueous solutions, over an extended concentration range, from the dilute to the semidilute regime.

show abstract

Section: Poor Solvent Conditionmentioning

confidence: 82%

Does Electrical Conductivity of Linear Polyelectrolytes in Aqueous Solutions Follow the Dynamic Scaling Laws? A Critical Review and a Summary of the Key Relations

Cametti

2014

Polymers

View full text Add to dashboard Cite

show abstract

“…contraction of the polyelectrolyte was induced by chemical variation of the charge fraction on the polyelectrolyte chains [18][19][20], by lowering the pH [21], by addition of an organic solvent to aqueous solutions [24] or by addition of an inert salt [27]. Only some of those authors attempted to explicitly discriminate between compact spheres and pearl necklace chains [18,23,24,27], or at least considered their results to be a consequence of pearl necklace chains [17,20,21].…”

mentioning

confidence: 99%

Shrinking of anionic polyacrylate coils induced by Ca2+, Sr2+ and Ba2+: A combined light scattering and ASAXS study

2006

View full text Add to dashboard Cite

Abstract. Anionic polyacrylate chains (NaPA) form precipitates if alkaline earth cations are added in stoichiometric amounts. Accordingly, precipitation thresholds were established for three different alkaline earth cations Ca 2+, Sr 2+ and Ba 2+. Close to the precipitation threshold, the NaPA chains significantly decrease in size. This shrinking process was followed by means of combined static and dynamic light scattering. Intermediates were generated by varying the ratio MCl 2 /[NaPA] with M denoting the respective alkaline earth cation. All experiments were performed at an inert salt level of 0.01 M NaCl. Similar coil -to -sphere transitions could be observed with all three alkaline earth cations Ca 2+ , Sr 2+ and Ba 2+. Based on these findings, supplementary conventional and anomalous small angle x-ray scattering experiments using selected intermediates close to the precipitation threshold of SrPA were performed. The distribution of Sr-counterions around the polyacrylate chains in aqueous solution provided the desired scattering contrast. Energy dependent scattering experiments enabled successful separation of the pure-resonant terms, which solely stem from the counterions. The Sr 2+ scattering roughly reflects the monomer distribution of the polyacrylate chains. Different ratios of the concentrations of [SrCl 2 ]/[NaPA] revealed dramatic changes in the scattering curves. The scattering curve at the lowest ratio indicated an almost coil-like behaviour, while at the higher ratios the scattering curves supported the model of highly contracted polymer chains. Most of X-ray scattering experiments on intermediate states revealed compact structural elements which were significantly smaller than the respective overall size of the NaPA particles.

show abstract

“…In fact, Equation (10) yields the same invariant and, along with it, the full number N of scattering Pb 2+ ions as the numerical integration of the simulated ASAXS curves does if extended over the entire q-regime of 0 nm´1 ď q ď q max with q max = 136 nm´1. In a truncated range of q of 0 ď q ď 2 nm´1 or of 0 ď q ď 10 nm´1 the resulting invariant contribution recovers a certain number of Pb 2+ ions N R which offers insight into the extent of completeness of the respective estimate as N R /N = ε given in Equation (11). Figure 5 summarizes, quantitatively, the results from the MC simulations with four different cubic confinements with edge lengths of 1, 2, 4, and 6.5 nm respectively.…”

Section: Discussionmentioning

confidence: 91%

“…qmax with qmax = 136 nm −1 . In a truncated range of q of 0 < q < 2 nm −1 or of 0 < q < 10 nm −1 the resulting invariant contribution recovers a certain number of Pb 2+ ions NR which offers insight into the extent of completeness of the respective estimate as NR/N = ε given in Equation (11). Figure 5 summarizes, quantitatively, the results from the MC simulations with four different cubic confinements with edge lengths of 1, 2, 4, and 6.5 nm respectively.…”

Section: Discussionmentioning

confidence: 92%

See 1 more Smart Citation

Systematic Limitations in Concentration Analysis via Anomalous Small-Angle X-ray Scattering in the Small Structure Limit

2016

View full text Add to dashboard Cite

Anomalous small angle scattering measurements have been applied to diluted solutions of anionic polyacrylates decorated by specifically-interacting Pb 2+ cations, revealing partial collapse of the polyacrylate into pearl-like subdomains with a size on the order of a few nanometers. From the pure-resonant scattering contribution of the Pb 2+ cations, and from subsequent analysis of the resonant-invariant, the amount of Pb 2+ cations condensed onto the polyanions with respect to the total amount of Pb 2+ cations in the solvent was estimated. In order to scrutinize systematic limitations in the determination of the chemical concentrations of resonant scattering counterions in the collapsed phase, Monte Carlo simulations have been performed. The simulations are based on structural confinements at variable size in the range of few nanometers, which represent the collapsed subdomains in the polyanions. These confinements were gradually filled to a high degree of the volume fraction with resonant scattering counterions giving access to a resonant-invariant at a variable degree of filling. The simulations revealed in the limit of small structures a significant underestimation of the true degree of filling of the collapsed subdomains when determining chemical concentrations of Pb 2+ cations from the resonant invariant.

show abstract

Neutron Scattering Studies of the Structure of a Polyelectrolyte Globule in a Water−Acetone Mixture

Cited by 61 publications

References 16 publications

Does Electrical Conductivity of Linear Polyelectrolytes in Aqueous Solutions Follow the Dynamic Scaling Laws? A Critical Review and a Summary of the Key Relations

Does Electrical Conductivity of Linear Polyelectrolytes in Aqueous Solutions Follow the Dynamic Scaling Laws? A Critical Review and a Summary of the Key Relations

Shrinking of anionic polyacrylate coils induced by Ca2+, Sr2+ and Ba2+: A combined light scattering and ASAXS study

Systematic Limitations in Concentration Analysis via Anomalous Small-Angle X-ray Scattering in the Small Structure Limit

Contact Info

Product

Resources

About