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Item type:Publication, Access status: without files , Theory and modeling of transport for simple fluids in nanoporous materials: from microscopic to coarse-grained descriptions(American Chemical Society (ACS), 2025-02-18); ; We present the state-of-the-art of theoretical modeling, molecular simulation, and coarse-graining strategies for the transport of gases and liquids in nanoporous materials (pore size 1-100 nm). Special emphasis is placed on the transport of small molecules in zeolites, active carbons, metal-organic frameworks, but also in nanoporous materials with larger pores such as ordered and disordered mesoporous oxides. We present different atomistic and mesoscopic methods as well as available theoretical formalisms to describe such a complex problem. Attention is given to the investigation of different molecular transport coefficients─including the self, collective and transport diffusivities─but also to the determination of free energy barriers and their role in overall adsorption/separation process rates. We further introduce other available approaches such as hierarchical simulations and upscaling strategies. This review focuses on simple fluids in prototypical nanoporous materials. While the phenomena covered here capture the main physical mechanisms in such systems, complex molecules will exhibit additional specific features. For the sake of clarity and brevity, we also omit multicomponent systems (e.g., fluid mixtures, electrolytes, etc.) and electrokinetic effects arising when charged systems are considered (ionic species, charged surfaces, etc.), both of which add to the complexity.Publicationtype: Review Article49 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Disentanglement of Surface and Confinement Effects for Diene Metathesis in Mesoporous ConfinementWe study the effects of a planar interface and confinement on a generic catalytically activated ring-closing polymerization reaction near an unstructured catalyst. For this, we employ a coarse-grained polymer model using grand-canonical molecular dynamics simulations with a Monte Carlo reaction scheme. Inspired by recent experiments in the group of M. Buchmeiser that demonstrated an increase in ring-closing selectivity under confinement, we show that both the interface effects, i.e., placing the catalyst near a planar wall, and the confinement effects, i.e., locating the catalyst within a pore, lead to an increase of selectivity. We furthermore demonstrate that curvature effects for cylindrical mesopores (2 nm < d < 12.3 nm) influence the distribution of the chain ends, leading to a further increase in selectivity. This leads us to speculate that specially corrugated surfaces might also help to enhance catalytically activated polymerization processes.Publicationtype: Journal Article10 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Solvent Effects on Structure and Screening in Confined Electrolytes(American Physical Society (APS), 2023-09-11); 12 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , A screening of results on the decay length in concentrated electrolytes(Royal Society of Chemistry (RSC), 2023-08-21); 12 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , The presence of a wall enhances the probability for ring-closing metathesis: insights from classical polymer theory and atomistic simulations(2020-12-06); ; The probability distribution of chain ends meeting when one end of the polymer is fixed to a certain distance to a reflecting wall is investigated. For an ideal polymer chain the probability distribution can be evaluated analytically via classic polymer theory. These analytical predictions are compared to atomistic MD simulations of one tethered alkane chain close to the wall. The results demonstrate that a confining wall can lead to a significant increase in the return probability for the chain ends, and thus, can increase the occurrence of ring-closing reactions. It is further demonstrated that the excess return probability shows a maximum at a certain distance, thereby yielding an optimal catalyst position in the ring-closing reaction.Publicationtype: Journal Article7