Highly Altered State of Proton Transport in Acid Pools in Charged Reverse Micelles

Publikation: Beitrag in FachzeitschriftForschungsartikelBeigetragenBegutachtung

Beitragende

Abstract

Transport mechanisms of solvated protons of 1 M HCl acid pools, confined within reverse micelles (RMs) containing the negatively charged surfactant sodium bis(2-ethylhexyl) sulfosuccinate (NaAOT) or the positively charged cetyltrimethylammonium bromide (CTABr), are analyzed with reactive force field simulations to interpret dynamical signatures from TeraHertz absorption and dielectric relaxation spectroscopy. We find that the forward proton hopping events for NaAOT are further suppressed compared to a nonionic RM, while the Grotthuss mechanism ceases altogether for CTABr. We attribute the sluggish proton dynamics for both charged RMs as due to headgroup and counterion charges that expel hydronium and chloride ions from the interface and into the bulk interior, thereby increasing the pH of the acid pools relative to the nonionic RM. For charged NaAOT and CTABr RMs, the localization of hydronium near a counterion or conjugate base reduces the Eigen and Zundel configurations that enable forward hopping. Thus, localized oscillatory hopping dominates, an effect that is most extreme for CTABr in which the proton residence time increases dramatically such that even oscillatory hopping is slow.

Details

OriginalspracheEnglisch
Seiten (von - bis)1826-1834
Seitenumfang9
FachzeitschriftJournal of the American Chemical Society
Jahrgang145
Ausgabenummer3
PublikationsstatusVeröffentlicht - 12 Jan. 2023
Peer-Review-StatusJa

Externe IDs

Scopus 85146330582
WOS 000918806100001
ORCID /0000-0002-8120-8553/work/142251735

Schlagworte

Schlagwörter

  • Hydrated excess protons, Hydroxide ions, Water, Dynamics, Spectroscopy, Solvation, Model, Confinement, Grotthuss, Membranes