Explaining Giant Apparent pKa Shifts in Weak Polyelectrolyte Brushes

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11310%2F23%3A10471107" target="_blank" >RIV/00216208:11310/23:10471107 - isvavai.cz</a>

Výsledek na webu

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=f_2li7QVur" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=f_2li7QVur</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1103/PhysRevLett.131.168101" target="_blank" >10.1103/PhysRevLett.131.168101</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Explaining Giant Apparent pKa Shifts in Weak Polyelectrolyte Brushes

Popis výsledku v původním jazyce

Recent experiments on weak polyelectrolyte brushes found marked shifts in the effective pKa that are linear in the logarithm of the salt concentration. Comparing explicit-particle simulations with mean-field calculations we show that for high grafting densities the salt concentration effect can be explained using the ideal Donnan theory, but for low grafting densities the full shift is due to a combination of the Donnan effect and the polyelectrolyte effect. The latter originates from electrostatic correlations that are neglected in the Donnan picture and that are only approximately included in the mean-field theory. Moreover, we demonstrate that the magnitude of the polyelectrolyte effect is almost invariant with respect to salt concentration but depends on the grafting density of the brush. This invariance is due to a complex cancellation of multiple effects. Based on our results, we show how the experimentally determined pKa shifts may be used to infer the grafting density of brushes, a parameter that is difficult to measure directly.

Název v anglickém jazyce

Explaining Giant Apparent pKa Shifts in Weak Polyelectrolyte Brushes

Popis výsledku anglicky

Recent experiments on weak polyelectrolyte brushes found marked shifts in the effective pKa that are linear in the logarithm of the salt concentration. Comparing explicit-particle simulations with mean-field calculations we show that for high grafting densities the salt concentration effect can be explained using the ideal Donnan theory, but for low grafting densities the full shift is due to a combination of the Donnan effect and the polyelectrolyte effect. The latter originates from electrostatic correlations that are neglected in the Donnan picture and that are only approximately included in the mean-field theory. Moreover, we demonstrate that the magnitude of the polyelectrolyte effect is almost invariant with respect to salt concentration but depends on the grafting density of the brush. This invariance is due to a complex cancellation of multiple effects. Based on our results, we show how the experimentally determined pKa shifts may be used to infer the grafting density of brushes, a parameter that is difficult to measure directly.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10403 - Physical chemistry

Projekt

<a href="/cs/project/GC21-31978J" target="_blank" >GC21-31978J: Simulace reakčních rovnováh v polymerních systémech - vývoj simulačních metod a jejich aplikace</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2023

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Physical Review Letters

ISSN

0031-9007

e-ISSN

1079-7114

Svazek periodika

131

Číslo periodika v rámci svazku

16

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

6

Strana od-do

168101

Kód UT WoS článku

001105904700003

EID výsledku v databázi Scopus

2-s2.0-85175819798