Investigating the Temperature-Induced Expansion of MIL-53 under Different Gas Environments Using Molecular Simulations

The phase change behavior of materials has resulted in exciting implications for materials science, especially for materials that show negative thermal expansion and gate opening. To explore these properties, molecular simulation has enabled an atomistic-level understanding of these dynamic materials. However, conventional Monte Carlo and molecular dynamics simulations fall short in capturing both the adsorption properties and the flexibility of the framework. This is crucial for porous materials that can adsorb and desorb guests, which can influence, or even trigger, phase changes. In this work, we employed and refined a novel hybrid Monte Carlo/molecular dynamics scheme to successfully investigate the dynamics of MIL-53 under helium, argon, and carbon dioxide atmospheres across a range of temperatures. Our findings provide new insights into tuning the expansion properties and uncovering intermediate phases, paving the way for advancements in the design and application of porous materials under realistic conditions.