Molecular velocity auto-correlations in glycerol/water mixtures studied by NMR MGSE method

Stepišnik, Janez (author), Mattea, Carlos (author), Stapf, Siegfried (author), Mohorič, Aleš (author)

Molecular dynamics in binary mixtures of water and glycerol was studied by measuring the spectrum of water velocity auto-correlation in the frequency range from 0.05 − 10 kHz by using the NMR method of modulated gradient spin echo. The method shows that the diversity of diffusion signature in the short spin trajectories provides information about heterogeneity of molecular motion due to the motion in the micro-vortexes of hydrodynamic fluctuation, which is especially pronounced for the mixtures with low glycerol content. As concentration of glycerol increases above 10vol%, a new feature of spectrum appears due to interaction of water molecules with the clusters formed around hydrophilic glycerol molecules. New spectrum exposes a rate thickening of molecular friction, according to Einstein–Smoluchowski–Kubo formula, which inhibits rapid molecular motions and creates the conditions for a slow process of spontaneously folding of disordered poly-peptides into biologically active protein molecules when immersed in such a mixture.

• Language: English
• Keywords: molecular dynamics, nuclear magnetic resonance, MGSE method, glycerol/water mixture, NMR, gradient spin-echo, self-diffusion, molecular velocity auto-correlation, shear rate viscosity thickening, protein folding
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FMF - Faculty of Mathematics and Physics
• Publication status: Published
• Publication version: Version of Record
• Year: 2020
• Number of pages: 12 str.
• Numbering: Vol. 553, art. 124171
• PID: 20.500.12556/RUL-137731
• UDC: 543.429.23
• ISSN on article: 0378-4371
• DOI: 10.1016/j.physa.2020.124171
• COBISS.SI-ID: 19363843
• Publication date in RUL: 29.06.2022

Record is a part of a journal

• Title: Physica. A, Statistical mechanics and its applications
• Shortened title: Physica, A
• Publisher: Elsevier
• ISSN: 0378-4371
• COBISS.SI-ID: 3270415

Licences

• License: CC BY-NC-ND 4.0, Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
• Link: http://creativecommons.org/licenses/by-nc-nd/4.0/
• Description: The most restrictive Creative Commons license. This only allows people to download and share the work for no commercial gain and for no other purposes.

Secondary language

• Language: Slovenian
• Keywords: molekulska dinamika, jedrska magnetna resonanca, metoda MGSE

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: P1-0060
• Name: Eksperimentalna biofizika kompleksnih sistemov in slikanje v biomedicini