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Molecular Dynamics Study of the Green Solvent Polyethylene Glycol with Water Impurities

Hoffmann, Markus M. ; Too, Matthew D. ; Paddock, Nathaniel A. ; Horstmann, Robin ; Kloth, Sebastian ; Vogel, Michael ; Buntkowsky, Gerd (2024)
Molecular Dynamics Study of the Green Solvent Polyethylene Glycol with Water Impurities.
In: Molecules, 2024, 29 (9)
doi: 10.26083/tuprints-00027337
Artikel, Zweitveröffentlichung, Verlagsversion

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Kurzbeschreibung (Abstract)

Polyethylene glycol (PEG) is one of the environmentally benign solvent options for green chemistry. It readily absorbs water when exposed to the atmosphere. The Molecular Dynamics (MD) simulations of PEG200, a commercial mixture of low molecular weight polyethyelene glycol oligomers, as well as di-, tetra-, and hexaethylene glycol are presented to study the effect of added water impurities up to a weight fraction of 0.020, which covers the typical range of water impurities due to water absorption from the atmosphere. Each system was simulated a total of four times using different combinations of two force fields for the water (SPC/E and TIP4P/2005) and two force fields for the PEG and oligomer (OPLS-AA and modified OPLS-AA). The observed trends in the effects of water addition were qualitatively quite robust with respect to these force field combinations and showed that the water does not aggregate but forms hydrogen bonds at most between two water molecules. In general, the added water causes overall either no or very small and nuanced effects in the simulation results. Specifically, the obtained water RDFs are mostly identical regardless of the water content. The added water reduces oligomer hydrogen bonding interactions overall as it competes and forms hydrogen bonds with the oligomers. The loss of intramolecular oligomer hydrogen bonding is in part compensated by oligomers switching from inter- to intramolecular hydrogen bonding. The interplay of the competing hydrogen bonding interactions leads to the presence of shallow extrema with respect to the water weight fraction dependencies for densities, viscosities, and self-diffusion coefficients, in contrast to experimental measurements, which show monotonous dependencies. However, these trends are very small in magnitude and thus confirm the experimentally observed insensitivity of these physical properties to the presence of water impurities.

Typ des Eintrags: Artikel
Erschienen: 2024
Autor(en): Hoffmann, Markus M. ; Too, Matthew D. ; Paddock, Nathaniel A. ; Horstmann, Robin ; Kloth, Sebastian ; Vogel, Michael ; Buntkowsky, Gerd
Art des Eintrags: Zweitveröffentlichung
Titel: Molecular Dynamics Study of the Green Solvent Polyethylene Glycol with Water Impurities
Sprache: Englisch
Publikationsjahr: 13 Mai 2024
Ort: Darmstadt
Publikationsdatum der Erstveröffentlichung: 30 April 2024
Ort der Erstveröffentlichung: Basel
Verlag: MDPI
Titel der Zeitschrift, Zeitung oder Schriftenreihe: Molecules
Jahrgang/Volume einer Zeitschrift: 29
(Heft-)Nummer: 9
Kollation: 22 Seiten
DOI: 10.26083/tuprints-00027337
URL / URN: https://tuprints.ulb.tu-darmstadt.de/27337
Zugehörige Links:
Herkunft: Zweitveröffentlichung DeepGreen
Kurzbeschreibung (Abstract):

Polyethylene glycol (PEG) is one of the environmentally benign solvent options for green chemistry. It readily absorbs water when exposed to the atmosphere. The Molecular Dynamics (MD) simulations of PEG200, a commercial mixture of low molecular weight polyethyelene glycol oligomers, as well as di-, tetra-, and hexaethylene glycol are presented to study the effect of added water impurities up to a weight fraction of 0.020, which covers the typical range of water impurities due to water absorption from the atmosphere. Each system was simulated a total of four times using different combinations of two force fields for the water (SPC/E and TIP4P/2005) and two force fields for the PEG and oligomer (OPLS-AA and modified OPLS-AA). The observed trends in the effects of water addition were qualitatively quite robust with respect to these force field combinations and showed that the water does not aggregate but forms hydrogen bonds at most between two water molecules. In general, the added water causes overall either no or very small and nuanced effects in the simulation results. Specifically, the obtained water RDFs are mostly identical regardless of the water content. The added water reduces oligomer hydrogen bonding interactions overall as it competes and forms hydrogen bonds with the oligomers. The loss of intramolecular oligomer hydrogen bonding is in part compensated by oligomers switching from inter- to intramolecular hydrogen bonding. The interplay of the competing hydrogen bonding interactions leads to the presence of shallow extrema with respect to the water weight fraction dependencies for densities, viscosities, and self-diffusion coefficients, in contrast to experimental measurements, which show monotonous dependencies. However, these trends are very small in magnitude and thus confirm the experimentally observed insensitivity of these physical properties to the presence of water impurities.

Freie Schlagworte: polyethylene glycol, ethylene glycol oligomers, water impurity, hydrogen bonding, radial distribution functions, density, self diffusion, viscosity
ID-Nummer: Artikel-ID: 2070
Status: Verlagsversion
URN: urn:nbn:de:tuda-tuprints-273378
Zusätzliche Informationen:

This article belongs to the Special Issue Green Solvents as Emerging Substitutes: Preparation, Evaluation and Application

Sachgruppe der Dewey Dezimalklassifikatin (DDC): 500 Naturwissenschaften und Mathematik > 530 Physik
500 Naturwissenschaften und Mathematik > 540 Chemie
Fachbereich(e)/-gebiet(e): 05 Fachbereich Physik
05 Fachbereich Physik > Institut für Physik Kondensierter Materie (IPKM)
07 Fachbereich Chemie
07 Fachbereich Chemie > Eduard Zintl-Institut
07 Fachbereich Chemie > Eduard Zintl-Institut > Fachgebiet Physikalische Chemie
Hinterlegungsdatum: 13 Mai 2024 13:36
Letzte Änderung: 14 Mai 2024 06:45
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