Effects of Non-Ionic Micelles on the Acid-Base Equilibria of a Weak Polyelectrolyte

Yekymov, Evgenee; Attia, David; Levi‐Kalisman, Yael; Bitton, Ronit; Yerushalmi‐Rozen, Rachel

doi:10.3390/polym14091926

Cited by 3 publications

(2 citation statements)

References 64 publications

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“…Since macromolecular crowding can affect the reactivity and structure of biomacromolecules, one could expect a possible charge regulation response triggered by a sufficiently high macromolecular concentration. Only recently, this hypothesis has been examined by theoretical [ 73 ] and experimental [ 277 , 278 ] studies which have studied the ionization of weak polyelectrolytes and peptides under MCr, respectively. Let us first review the theoretical insights on the charge regulation response triggered by MCr and later contrast those insights with the experimental observations.…”

Section: Weak Polyelectrolytes In Crowded Systemsmentioning

confidence: 99%

“…The recent potentiometric titration experiments performed by Yekymov et al [ 277 , 278 ] of poly(acrylic acid) (PAA) in presence of MCr suggest significant influence of MCr on the ionization of the PE. They studied the ionization of PAA in solution with two different crowder agents: short chains of poly(vinyl alcohol) (PVA) and Carbon Black nanoparticles with PVA grafted on their surface (CB-PVA).…”

Section: Weak Polyelectrolytes In Crowded Systemsmentioning

confidence: 99%

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Unusual Aspects of Charge Regulation in Flexible Weak Polyelectrolytes

et al. 2023

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This article reviews the state of the art of the studies on charge regulation (CR) effects in flexible weak polyelectrolytes (FWPE). The characteristic of FWPE is the strong coupling of ionization and conformational degrees of freedom. After introducing the necessary fundamental concepts, some unconventional aspects of the the physical chemistry of FWPE are discussed. These aspects are: (i) the extension of statistical mechanics techniques to include ionization equilibria and, in particular, the use of the recently proposed Site Binding-Rotational Isomeric State (SBRIS) model, which allows the calculation of ionization and conformational properties on the same foot; (ii) the recent progresses in the inclusion of proton equilibria in computer simulations; (iii) the possibility of mechanically induced CR in the stretching of FWPE; (iv) the non-trivial adsorption of FWPE on ionized surfaces with the same charge sign as the PE (the so-called “wrong side” of the isoelectric point); (v) the influence of macromolecular crowding on CR.

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Section: Weak Polyelectrolytes In Crowded Systemsmentioning

confidence: 99%

Section: Weak Polyelectrolytes In Crowded Systemsmentioning

confidence: 99%

Unusual Aspects of Charge Regulation in Flexible Weak Polyelectrolytes

et al. 2023

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Self-assembly of mixed surfactants sodium dodecylsulfate and polyethylene glycol dodecyl ether in aqueous solutions

Teixeira,

Quintão,

Oliveira

et al. 2024

Journal of Molecular Liquids

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Charge Regulation of Poly(acrylic acid) in Solutions of Non-Charged Polymer and Colloids

et al. 2023

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Weak polyelectrolytes (WPEs) are responsive materials used as active charge regulators in a variety of applications, including controlled release and drug delivery in crowded bio-related and synthetic environments. In these environments, high concentrations of solvated molecules, nanostructures, and molecular assemblies are ubiquitous. Here, we investigated the effect of high concentrations of non-adsorbing, short chains of poly(vinyl alcohol), PVA, and colloids dispersed by the very same polymers on charge regulation (CR) of poly(acrylic acid), PAA. PVA does not interact with PAA (throughout the full pH range) and thus can be used to examine the role of non-specific (entropic) interactions in polymer-rich environments. Titration experiments of PAA (mainly 100 kDa in dilute solutions, no added salt) were carried out in high concentrations of PVA (13–23 kDa, 5–15 wt%) and dispersions of carbon black (CB) decorated by the same PVA (CB-PVA, 0.2–1 wt%). The calculated equilibrium constant (and pKa) was up-shifted in PVA solutions by up to ~0.9 units and down-shifted in CB-PVA dispersions by ~0.4 units. Thus, while solvated PVA chains increase the charging of the PAA chains, as compared to PAA in water, CB-PVA particles reduce PAA charging. To investigate the origins of the effect, we analyzed the mixtures using small-angle X-ray scattering (SAXS) and cryo-TEM imaging. The scattering experiments revealed re-organization of the PAA chains in the presence of the solvated PVA but not in the CB-PVA dispersions. These observations clearly indicate that the acid–base equilibrium and the degree of ionization of PAA in crowded liquid environments is affected by the concentration, size, and geometry of seemingly non-interacting additives, probably due to depletion and excluded volume interactions. Thus, entropic effects that do not depend on specific interactions should be taken into consideration when designing functional materials in complex fluid environments.

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Effects of Non-Ionic Micelles on the Acid-Base Equilibria of a Weak Polyelectrolyte

Cited by 3 publications

References 64 publications

Unusual Aspects of Charge Regulation in Flexible Weak Polyelectrolytes

Unusual Aspects of Charge Regulation in Flexible Weak Polyelectrolytes

Self-assembly of mixed surfactants sodium dodecylsulfate and polyethylene glycol dodecyl ether in aqueous solutions

Charge Regulation of Poly(acrylic acid) in Solutions of Non-Charged Polymer and Colloids

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