Precise control over gas transporting channels in zeolitic imidazolate framework glasses

Abstract

Porous materials, such as metal-organic frameworks emerge to solve important quests of our modern society, such as CO2 sequestration. Zeolitic Imidazolate Frameworks (ZIFs) can undergo a glass transition to form ZIF-glasses; they combine the liquid handling of classical glasses with tremendous potential for gas separations. Using millimeter-sized ZIF-62 single crystals and centimeter-sized ZIF-62-glass we demonstrate scalability and processability. Further, following the evolution of gas penetration into ZIF-crystals and ZIF-glasses by IR microimaging techniques enables to determine diffusion constants and changes to the pore architecture on the Angstrom-scale. The evolution of ZIF-glasses is observed in situ using a microscope heating stage. The pore-collapse during glass-processing is tracked by changes to density and volume of the glasses. Mass spectrometry investigates the crystal-to-glass transition and thermal processing ability.