Improving NMR cryoporometry with octamethylcyclotetrasiloxane: From network models to accurate thermodynamic parameters

Abstract

Nuclear magnetic resonance cryoporometry is capable of probing large-pore materials with pore sizes ranging from tens to thousands of nanometers. Achieving higher spatial sensitivity requires probe liquids with large solid–liquid interfacial energies, which are often poorly known. A representative example is octamethylcyclotetrasiloxane, which has attracted considerable interest for thermoporometry applications despite the wide scatter in the thermodynamic properties reported in the literature. In this work, we present an experimental approach for accurately determining these properties by exploiting recent advances in the description of solid–liquid equilibria in confined systems. The two proposed strategies provide highly consistent results and can be readily extended to other liquids with unknown thermodynamic properties.