Water binding and hygroscopicity in π-conjugated polyelectrolytes.

Autor: Tang CG; Department of Physics, National University of Singapore, Lower Kent Ridge Road, S117550, Singapore, Singapore., Syafiqah MN; Department of Chemistry, National University of Singapore, Lower Kent Ridge Road, S117552, Singapore, Singapore., Koh QM; Department of Chemistry, National University of Singapore, Lower Kent Ridge Road, S117552, Singapore, Singapore., Ang MC; Department of Chemistry, National University of Singapore, Lower Kent Ridge Road, S117552, Singapore, Singapore., Choo KK; Department of Chemistry, National University of Singapore, Lower Kent Ridge Road, S117552, Singapore, Singapore., Sun MM; Department of Chemistry, National University of Singapore, Lower Kent Ridge Road, S117552, Singapore, Singapore., Callsen M; Department of Physics, National University of Singapore, Lower Kent Ridge Road, S117550, Singapore, Singapore., Feng YP; Department of Physics, National University of Singapore, Lower Kent Ridge Road, S117550, Singapore, Singapore., Chua LL; Department of Chemistry, National University of Singapore, Lower Kent Ridge Road, S117552, Singapore, Singapore. chmcll@nus.edu.sg., Png RQ; Department of Physics, National University of Singapore, Lower Kent Ridge Road, S117550, Singapore, Singapore. ruiqi@nus.edu.sg., Ho PKH; Department of Physics, National University of Singapore, Lower Kent Ridge Road, S117550, Singapore, Singapore. phyhop@nus.edu.sg.
Jazyk: angličtina
Zdroj: Nature communications [Nat Commun] 2023 Jul 05; Vol. 14 (1), pp. 3978. Date of Electronic Publication: 2023 Jul 05.
DOI: 10.1038/s41467-023-39215-9
Abstrakt: The presence of water strongly influences structure, dynamics and properties of ion-containing soft matter. Yet, the hydration of such matter is not well understood. Here, we show through a large study of monovalent π-conjugated polyelectrolytes that their reversible hydration, up to several water molecules per ion pair, occurs chiefly at the interface between the ion clusters and the hydrophobic matrix without disrupting ion packing. This establishes the appropriate model to be surface hydration, not the often-assumed internal hydration of the ion clusters. Through detailed analysis of desorption energies and O-H vibrational frequencies, together with OPLS4 and DFT calculations, we have elucidated key binding motifs of the sorbed water. Type-I water, which desorbs below 50 °C, corresponds to hydrogen-bonded water clusters constituting secondary hydration. Type-II water, which typically desorbs over 50-150 °C, corresponds to water bound to the anion under the influence of a proximal cation, or to a cation‒anion pair, at the cluster surface. This constitutes primary hydration. Type-III water, which irreversibly desorbs beyond 150 °C, corresponds to water kinetically trapped between ions. Its amount varies strongly with processing and heat treatment. As a consequence, hygroscopicity-which is the water sorption capacity per ion pair-depends not only on the ions, but also their cluster morphology.
(© 2023. The Author(s).)
Databáze: MEDLINE
Externí odkaz: