Ion-specific effect on dynamics of polyelectrolyte chains

Luo, Zhenli; Wang, Xiaoyan; Zhang, Guangzhao

doi:10.1039/c2cp40077d

Cited by 17 publications

(16 citation statements)

References 55 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Next, for both ionene types (3,3 and 6,6), the binding constant increases in the order Cl − < Br − < I − . Interestingly, the same ordering of ions (Hofmeister series) was also found for lysozyme solutions, although the interacting groups there were different [39], and for other polyelectrolytes [52]. The findings of the present study corroborate the molecular dynamics simulations of the model ionene oligocations [50,51], where the affinity of the counterions for the ionene was found to increase in the order F…”

Section: Results Of the Thermodynamic (Model) Analysissupporting

confidence: 90%

Thermodynamic analysis of the interaction of partially hydrophobic cationic polyelectrolytes with sodium halide salts in water

et al. 2014

View full text Add to dashboard Cite

Isothermal titration calorimetry was used to determine the temperature and concentration dependence of the enthalpy of mixing of 3,3-and 6,6-ionene fluorides, bromides, and iodides with low molecular weight salts (NaF, NaCl, NaBr, and NaI) in water. The magnitudes of the enthalpies, measured in the temperature range from 273 to 318 K, depended on the number of methylene groups on the ionene polyion (hydrophobicity), and on the anion of the added salt (ion-specificity). All enthalpies of mixing of 3,3-and 6,6-ionene fluorides with low molecular weight salts (NaCl, NaBr, and NaI) were negative, which is in contrast to the predictions of standard theories of polyelectrolyte solutions. This fact was interpreted in the light of the ion-water short-range interactions that are not accounted for in those theories. In contrast, the enthalpies of mixing of 3,3-and 6,6-ionene bromides and iodides with NaF were positive, being in accord with theory. Using the calorimetric data, we performed a model thermodynamic analysis of the polyelectrolyte-salt mixing process to obtain changes in the apparent standard Gibbs free energy, enthalpy, entropy, and heat capacity relative to the pure ionene fluorides in water. The results prove that halide ions replace fluoride counterions with a strength increasing in the order chloride < bromide < iodide. The process is enthalpy governed, accompanied by a positive change in the heat capacity.

show abstract

Section: Results Of the Thermodynamic (Model) Analysissupporting

confidence: 90%

Thermodynamic analysis of the interaction of partially hydrophobic cationic polyelectrolytes with sodium halide salts in water

et al. 2014

View full text Add to dashboard Cite

show abstract

“…Similarly to the peak at 4.2 ppm, the resonance signals corresponding to the pyridinium units increase as the quaternization degree increases. Finally, in PVPQ, the peaks corresponding to PVP have completely disappeared confirming the quantitative quaternization of PVP [ 47 , 53 ]. Similar observations are drawn from the 13 C NMR spectra, Figure 3 b: the resonance signals attributed to PVP (155, 150 and 124 ppm) decrease as the quaternization degree increases and are totally missing from PVPQ spectra.…”

Section: Resultsmentioning

confidence: 99%

Poly(vinyl pyridine) and Its Quaternized Derivatives: Understanding Their Solvation and Solid State Properties

et al. 2022

View full text Add to dashboard Cite

A series of N-methyl quaternized derivatives of poly(4-vinylpyridine) (PVP) were synthesized in high yields with different degrees of quaternization, obtained by varying the methyl iodide molar ratio and affording products with unexplored optical and solvation properties. The impact of quaternization on the physicochemical properties of the copolymers, and notably the solvation properties, was further studied. The structure of the synthesized polymers and the quaternization degrees were determined by infrared and nuclear magnetic spectroscopies, while their thermal characteristics were studied by differential scanning calorimetry and their thermal stability and degradation by thermogravimetric analysis (TG-DTA). Attention was given to their optical properties, where UV-Vis and diffuse reflectance spectroscopy (DRS) measurements were carried out. The optical band gap of the polymers was calculated and correlated with the degree of quaternization. The study was further orientated towards the solvation properties of the polymers in binary solvent mixtures that strongly depend on the degree of quaternization, enabling a better understanding of the key polymer (solute)-solvent interactions. The assessment of the underlying solvation phenomena was performed in a system of different ratios of DMSO/H2O and the solvatochromic indicator used was Reichardt’s dye. Solvent polarity parameters have a significant effect on the visible spectra of the nitrogen quaternization of PVP studied in this work and a detailed path towards this assessment is presented.

show abstract

“…A second effect, which leads to a stabilization of the brushes are interchain interactions. The stabilization effect between pyridinium moieties and iodide has been monitored in form of a reduced enthalpy during a mixing experiment, where iodide is the only halide ion which has a negative mixing enthalpy with PMeVP. Furthermore, the formation of charge‐transfer complexes between iodide ions and pyridinium moieties suggest the possible existence of such interactions between the chains .…”

Section: Discussionmentioning

confidence: 99%

Entropic death of nonpatterned and nanopatterned polyelectrolyte brushes

Menzel

Chen

Simancas

et al. 2019

J. Polym. Sci. Part A: Polym. Chem.

View full text Add to dashboard Cite

The stability of nonpatterned and nanopatterned strong polyelectrolyte brushes (PEBs) is studied as a function of both brush character and the properties of a contacting liquid. High-molecularweight PEBs of poly(4-methyl vinylpyridinium iodide) (PMeVP) are synthesized using surface-initiated radical-chain polymerization. Nanopatterned brushes (NPBs) line with pattern sizes ranging from 50 to 200 nm are generated by patterning the initiator layer using deep-ultraviolet photolithography followed by brush growth initiated from the patterned layer. Homogeneous PEBs with different degrees of charging and grafting densities are exposed to water and salt solutions with different temperatures for different periods. The degradation is monitored through dry-state ellipsometry and atomic force microscopy measurements. Enhanced degrafting for more strongly swollen polymer brushes can be observed in agreement with an "entropic spring" model. Based on the results of the nonpatterned brushes, the NPBs are exposed to water at different temperatures and external salt content for varying periods of time. Counterintuitively, the NPBs show increased degrafting for smaller patterns, which is attributed to different polymer chain dynamics for nanobrushes and microbrushes. We investigate the influence of thermodynamic and kinetic parameters on the stability of (nanopatterned) PEBs and discuss the role of entanglements and formation of complexes in such films.The additional strong electrostatic interactions due to the charges are a reason for the unusual and versatile behavior of PEBs compared to their neutral peers. 12 Thus, if polymer brushes with similar structures are compared, while neutral polymer brushes can already stretch by up to 40% of their contour length, PELs can stretch even more and stretched values of more than 65% of the contour length have been observed. 13 Such strong stretching leads to a significant loss of entropy and completely changes the properties of the layers, rendering PEBs as an attractive molecular architecture. They are often used for applications in the field of biochemistry as most organic molecules synthesized by living organisms carry electrolyte groups themselves. Thus, PEBs have been used for the analysis and study of proteins, 14 DNA, 15 vitamins 16 and in gene, 16 and drug 17 delivery. In addition, they are also perfect candidates for applications in antifouling medical devices, 18 biosensing, 19 antibacterial coatings, 5 cell culture substrates, 20 stem cell Additional supporting information may be found in the online version of this article. † M. Menzel and W. -L. Chen contributed equally to this article.

show abstract

Ion-specific effect on dynamics of polyelectrolyte chains

Cited by 17 publications

References 55 publications

Thermodynamic analysis of the interaction of partially hydrophobic cationic polyelectrolytes with sodium halide salts in water

Thermodynamic analysis of the interaction of partially hydrophobic cationic polyelectrolytes with sodium halide salts in water

Poly(vinyl pyridine) and Its Quaternized Derivatives: Understanding Their Solvation and Solid State Properties

Entropic death of nonpatterned and nanopatterned polyelectrolyte brushes

Contact Info

Product

Resources

About