Unveiling the amorphization of sodalite topology zeolitic imidazolate frameworks and zeolites by pressure and stress

As a flexible porous material, the amorphous behavior of zeolitic imidazolate framework-8 (ZIF-8) has garnered considerable interest. However, the association between its strain behavior and topology has not yet been exhaustively studied computationally. We perform molecular dynamic simulations on both ZIF-8 and its topological silicate isomer sodalite (SOD) to investigate the pressure-induced development of the mid- and short-range structures. We find that both ZIF-8 and SOD undergo two successive transformations. The first is the amorphization process, which is characterized by the breakdown of the mid-range structure without a significant change in the elastic modulus. The other type of densification involves a change in the short-range structure, during which the mechanical properties are improved as the short-range disorder increases.