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Updated: Sep 25, 2025

In Situ Monitoring of Diffusion of Guest Molecules in Porous Media Using Electron Paramagnetic Resonance Imaging
Published on: September 2, 2016
Molecular probe dynamics and free volume heterogeneities in n-propanol confined in a regular MCM-41 matrix by ESR and
Josef Bartoš1, Helena Švajdlenková1, Ondrej Šauša2
1Polymer Institute of SAS Dúbravská Cesta 9 SK-845 41 Bratislava Slovakia Jozef.Bartos@savba.sk.
Abstract:
A combined investigation of the spin probe TEMPO mobility and the free volume holes in n-propanol (n-PrOH) confined in a regular virgin MCM-41 matrix by means of ESR or PALS techniques, respectively, is reported. Dynamics of spin probe TEMPO alters at several characteristic ESR temperatures which are close to the characteristic PALS ones reflecting the changes in o-Ps annihilation and the related free volume. Correlations between these characteristic ESR and PALS temperatures indicate the common physical origins of the respective changes in the free volume expansion and the TEMPO mobility in the confined liquid n-PrOH. The significant difference in dynamic heterogeneity of TEMPO after confinement and free volume dispersion reflect the strongly altered structural-dynamic relationships in the confined n-PrOH medium with respect to the bulk situation.
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