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In this study, the adsorption mechanism of water in the metal–organic framework NU-1000 was investigated using molecular simulations. The simulations predict a significant impact of small changes in terminal aquo ligand orientation on the shape and pressure of the condensation step in the water adsorption isotherm. The analysis revealed that the rotational mobility of aquo ligands, often neglected in computational studies, can shift the condensation step by up to 20% in the relative humidity scale. By examining adsorption modes and interaction sites, it was demonstrated that configurational changes in the Zr6O8 node affect water adsorption significantly and can change the nature of the interactions from hydrophobic to hydrophilic. We propose a robust approach to account for these changes in simulations, achieving good agreement with experimental results. This work underscores the necessity of considering local, molecular flexibility in water adsorption simulations to avoid mischaracterization of MOFs’ water adsorption properties. 

ABSTRACT Animal muscle is an intriguing natural material whose mechanical properties arise from sequence‐diverse protein domains, many of which remain unexplored for material design. Among them, Immunoglobulin‐like (Ig) domains act as molecular springs that can unfold and refold repetitively without losing function, dissipating mechanical energy as heat, making them promising building blocks for next‐generation protein‐based materials (PBMs). In this study, we translate these molecular features to the macroscale by fabricating fibers from microbially‐synthesized Ig domains of various muscle proteins. Among them, Filamin‐derived Ig fibers (M_W = 123 kDa) exhibited a unique combination of high tensile strength (412 ± 22 MPa), high toughness (120 ± 17 MJ/m³), remarkable mechanical stability (∼89%) under 90% humidity, high energy damping capacity (∼80%), and complete shape recovery (∼100%) over repeated loading–unloading cycles. Our results further revealed molecular mechanisms underlying these properties: (i) Ig domain hydrophobicity strongly correlates with fiber assembly and tensile strength, (ii) reversible unfolding–refolding of Ig domains enables efficient energy dissipation and self‐recovery, and (iii) hydrogen‐bonding networks within the amorphous matrix regulate humidity‐induced weakening. Together, these findings establish Ig domains as a new class of PBMs combining advantageous mechanical and physical properties, offering a versatile platform for developing advanced materials with tunable performance. 

Abstract This review spotlights the role of atomic‐level modeling in research on metal‐organic frameworks (MOFs), especially the key methodologies of density functional theory (DFT), Monte Carlo (MC) simulations, and molecular dynamics (MD) simulations. The discussion focuses on how periodic and cluster‐based DFT calculations can provide novel insights into MOF properties, with a focus on predicting structural transformations, understanding thermodynamic properties and catalysis, and providing information or properties that are fed into classical simulations such as force field parameters or partial charges. Classical simulation methods, highlighting force field selection, databases of MOFs for high‐throughput screening, and the synergistic nature of MC and MD simulations, are described. By predicting equilibrium thermodynamic and dynamic properties, these methods offer a wide perspective on MOF behavior and mechanisms. Additionally, the incorporation of machine learning (ML) techniques into quantum and classical simulations is discussed. These methods can enhance accuracy, expedite simulation setup, reduce computational costs, as well as predict key parameters, optimize geometries, and estimate MOF stability. By charting the growth and promise of computational research in the MOF field, the aim is to provide insights and recommendations to facilitate the incorporation of computational modeling more broadly into MOF research. 

CALF-20, a Zn-triazolate-based metal-organic framework (MOF), is one of the most promising adsorbent materials for CO2 capture. However, competitive adsorption of water severely limits its performance when the relative humidity (RH) exceeds 40%, limiting the potential implementation of CALF-20 in practical settings where CO2 is saturated with moisture, such as post-combustion flue gas. In this work, three newly designed MOFs related to CALF-20, denoted as NU-220, CALF-20M-w, and CALF-20M-e that feature hydrophobic methyl-triazolate linkers are presented. Inclusion of methyl groups in the linker is proposed as a strategy to improve CO2 uptake in the presence of water. Notably, both CALF-20M-w and CALF-20M-e retain over 20% of their initial CO2 capture efficiency at 70% RH – a threshold at which CALF-20 shows negligible CO2 uptake. Grand canonical Monte Carlo (GCMC) simulations reveal that the methyl group hinders water network formation in the pores of CALF-20M-w and CALF-20M-e and enhances their CO2 selectivity over N2 in the presence of high moisture content. Moreover, calculated radial distribution functions indicate that introducing the methyl group into the triazolate linker increases the distance between water molecules and Zn coordination bonds, offering insights into the origin of the enhanced moisture stability observed for CALF-20M-w and CALF-20M-e relative to CALF-20. Overall, this straightforward design strategy has afforded more robust sorbents that can potentially meet the challenge of effectively capturing CO2 in practical industrial applications.