Scientists at the G. K. Boreskov Institute of Catalysis (IC SB RAS) and the NSU Physics Department Laboratory for Structures and Functional Properties of Molecular Systems studied in the structure of the ZIF-8 metal-organic framework when reduced to a partially amorphous state - glass. Japanese scientists synthesized Glass from microporous material. The results of this joint work by Novosibirsk and Kyoto University researchers was published in the journal Chem Comm (impact factor - 6.290).
Glass has an important industrial function. The number of potential applications for crystal structures increases tenfold when it is transformed into glass. Glass lends itself to geometric formations and has a greater density and integrity (compared to synthesized crystalline membranes). Crystals require binding material to maintain the desired form. Absorption membranes are even more complicated due to their inability to compress the membrane. Scientists create polymers to provide a base for the crystalline membrane, but this material can disintegrate and allow substances to pass through.
Japanese scientists took the first steps in manufacturing glass from crystalline materials. Over the past four years, they made a breakthrough creating glass that largely retains the porous properties of crystals but is also suitable for molding. Novosibirsk researchers studied the dynamic structure of this new phase state.
Daniil Kolokolov, Senior Researcher NSU Physics Department Laboratory for Structures and Functional Properties of Molecular Systems and IC SB RAS, talked about this research,
The creation of glass from hybrid materials is a nontrivial phenomenon because at 500 ° C organic matter will simply burn. Special conditions were identified that made porous glass possible. This product can be used to regulate the permeability of various reactors and pipes to increase the efficiency of cleaning substances. However, unlike crystal, the structure of glass is not ordered so using the available Novosibirsk scientific center resources, we are trying to understand how and why this material works, and why some types of metal-organic frameworks transform into glass and others that look like them do not.
Siberian scientists studied the partially amorphous material obtained from ZIF-8 crystal that was promising in relation to hydrocarbon separation processes. It turned out that the local structure of the material is preserved, but the dynamics of the structural object changes, the mobility of the passing windows increases and new types of movement appear.
Kolokolov provided more detail,
The windows mobility increases due to the amorphous material so it can be used to absorb larger substances. The material was distorted locally which affected the organic structures, linkers became much more mobile. The older types of movement accelerated. This modification helped to change the parameters for passing through windows by reducing the barrier.
The changes were recorded by NSU and IC SB RAS scientists using the unique solid-state nuclear magnetic resonance spectroscopy method to demonstrate how the crystal mobility changes. By studying glass in this way, we provide science with more in-depth and detailed information about the properties of existing glass. Novosibirsk researchers have demonstrated that the dynamics are sensitive to the structure of the new state. This approach can be applied to similar glass materials and expand their potential and the scope of application for these substances and this should attract industrial interest to the results of the research.
With our colleagues, we were able to achieve a method for synthesizing partially disordered structures similar to glass. We were able to show clearly how the process of disorder affects the local structure of these materials at the molecular level. In particular, we were able to prove that this partial randomness accelerates internal dynamic processes. This has the potential to provide a way to increase the permeability rate of these materials and the devices based on them.
This research was conducted with support from the Russian Science Foundation (project No. 17-73-10135).