A ¹³C NMR Study of the Molecular Dynamics and Phase Transition of Confined Benzene inside Titanate Nanotubes

Abstract

This work investigated the nanoconfinement effect on the molecular dynamics and phase transition of confined benzene inside titanate nanotubes with a uniform inner diameter of approximately 5.3 nm. For 13C-enriched organics, the 13C nuclear spin-spin relaxation was demonstrated as a sensitive tool to differentiate molecular translational motion and reorientation and, thus, was shown to be advantageous over the commonly employed 1H and 2H NMR for studying complex phase diagram, specifically, for separating the phase behavior of translational motion and the phase behavior of molecular reorientation. In such an approach, the melting of translational motion of confined benzene was explicitly observed to take place in a broad temperature range below the bulk melting temperature. The abrupt change of the 13C nuclear spin-spin relaxation time of the confined liquid benzene at about 260 K suggested that nanoconfinement induced two topologically distinct liquid phases.

Phase Transitions of Naphthalene and Its Derivatives Confined in Mesoporous Silicas

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2H NMR study of 2D melting and dynamic behaviour of CDCl3 confined in ACF nanospace

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Molecular Length Dependence of the Melting Temperature Elevation for the Encapsulated Linear Monocarboxylic Acids inside Titania Nanotubes

“…Confined materials in narrow pores exhibit − interesting physicochemical phenomena and are of potential applications. Of the encapsulated molecules in the pore, these adsorbed on the pore surface are subject to direct interaction with the pore wall and may be used to passivate the pore surface.…”