» Articles » PMID: 15007675

Confinement of Molecular Liquids: Consequences on Thermodynamic, Static and Dynamical Properties of Benzene and Toluene

Overview
Publisher EDP Sciences
Specialty Biophysics
Date 2004 Mar 10
PMID 15007675
Citations 9
Authors
Affiliations
Soon will be listed here.
Abstract

We relate the dynamical behavior of molecular liquids confined in mesoscopic cylindrical pores to the thermodynamic properties, heat capacity and density and to the static structure by combining different experimental methods (H-NMR, calorimetry, elastic and inelastic neutron scattering, numerical simulations). The crystallization process is greatly reduced or avoided by confinement under standard cooling conditions, instead a glass transition temperature T(g) at the 1000s time scale can be observed. The pore averaged local structure of the confined liquid is not noticeably affected when "excluded-volume" corrections are carefully applied, but follows the density changes reflected by the Bragg peak intensities of the porous matrices. The pore size dependence of T(g) is dominated by two factors, surface interaction and finite-size effect. For the smallest pores ([Formula: see text], [Formula: see text] being the van der Waals radius of a molecule), one observes an increase of T(g) and a broadening of the transition region, related to the interaction with the surface that induces a slowing-down of the molecules close to the wall. This is confirmed by neutron scattering experiments and molecular-dynamics simulations at shorter time scales and higher temperatures, which indicate a remaining fraction of frozen molecules. For larger pore sizes, taking the decrease of density under confinement conditions into account, a decrease of T(g) is observed. This could be related to finite-size effects onto the putative cooperativity length that is often invoked to explain glass formation. However, no quantitative determination of this length (not to mention its T-dependence) can be extracted, since the interaction with the wall itself introduces an additional length that adds to the complexity of the problem.

Citing Articles

Three-Dimensionally Printed Mini Air Scrubbing Cartridges Based on Nano-Graphite for Air Pollution Monitoring.

Zampetti E, Ammiraglia M, Conti M, Montiroli C, Papa P, Bianconi D Sensors (Basel). 2025; 25(1.

PMID: 39796913 PMC: 11723352. DOI: 10.3390/s25010122.


Probing the Behaviour of Fluids Confined in Porous Materials by Neutron Scattering: Applications to CO Sequestration and Enhanced Oil and Gas Recovery.

Stefanopoulos K Chempluschem. 2024; 89(12):e202400353.

PMID: 39206570 PMC: 11639646. DOI: 10.1002/cplu.202400353.


A Combined Atomic and Molecular Probe Characterization of Aromatic Hydrocarbons via PALS and ESR: Methylbenzene.

Bartos J, Zgardzinska B, Svajdlenkova H, Charmas B, Lukesova M, Wysoglad K Materials (Basel). 2022; 15(2).

PMID: 35057182 PMC: 8777640. DOI: 10.3390/ma15020462.


Effect of Surface Chemistry on the Glass-Transition Dynamics of Poly(phenyl methyl siloxane) Confined in Alumina Nanopores.

Winkler R, Tu W, Laskowski L, Adrjanowicz K Langmuir. 2020; 36(26):7553-7565.

PMID: 32515976 PMC: 7588132. DOI: 10.1021/acs.langmuir.0c01194.


Confinement Effects on the Benzene Orientational Structure.

Falkowska M, Bowron D, Manyar H, Youngs T, Hardacre C Angew Chem Int Ed Engl. 2018; 57(17):4565-4570.

PMID: 29446870 PMC: 6099463. DOI: 10.1002/anie.201713115.