Molecular probe dynamics and free volume heterogeneities in n-propanol confined in a regular MCM-41 matrix by ESR and PALS

Josef Bartoš; Helena Švajdlenková; Ondrej Šauša

doi:10.1039/c9ra09495d

Molecular probe dynamics and free volume heterogeneities in n-propanol confined in a regular MCM-41 matrix by ESR and PALS

RSC Adv. 2020 Jan 13;10(4):2283-2294. doi: 10.1039/c9ra09495d. eCollection 2020 Jan 8.

Authors

Josef Bartoš¹, Helena Švajdlenková¹, Ondrej Šauša²

Affiliations

¹ Polymer Institute of SAS Dúbravská Cesta 9 SK-845 41 Bratislava Slovakia Jozef.Bartos@savba.sk.
² Institute of Physics of SAS Dúbravská Cesta 9 SK-845 11 Bratislava Slovakia.

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.