Flux Melting of Metal-Organic Frameworks

<div>Recent demonstrations of melting in the metal-organic framework (MOF) family have created</div><div>interest in the interfacial domain between inorganic glasses and amorphous organic polymers. The</div><div>chemical and physical behaviour of porous hybrid liquids and glasses is of particular interest,</div><div>though opportunities are limited by the inaccessible melting temperatures of many MOFs. Here,</div><div>we show that the synthetic processing technique of flux melting, ‘borrowed’ from the inorganic</div><div>domain, may be applied to MOFs in order to melt materials which do not possess an accessible</div><div>liquid state in their pure form. We employ the high-temperature liquid state of one MOF as a solvent</div><div>for a secondary, non-melting MOF component. Differential scanning calorimetry, small- and wideangle</div><div>X-ray scattering, electron microscopy and X-ray total scattering techniques are used to show</div><div>the flux melting of the crystalline component within the liquid. Gas adsorption and positron</div><div>annihilation lifetime spectroscopy measurements show that this results in enhanced, accessible</div><div>porosity to a range of guest molecules, in the resultant flux melted MOF glass.</div>