吸附
解吸
结晶度
化学物理
材料科学
磁滞
弹性模量
多孔性
化学工程
化学
物理化学
复合材料
凝聚态物理
物理
工程类
作者
Kota Mitsumoto,Kyohei Takae
出处
期刊:Cornell University - arXiv
日期:2022-11-07
标识
DOI:10.48550/arxiv.2211.03370
摘要
Metal--organic frameworks (MOFs), which possess a high degree of crystallinity and a large surface area with tunable inorganic nodes and organic linkers, exhibit high stimuli-responsiveness and molecular adsorption selectivity that enable various applications. The adsorption in MOFs changes the crystalline structure and elastic moduli. Thus, the coexistence of adsorbed/desorbed sites makes the host matrices elastically heterogeneous. However, the role of elastic heterogeneity in the adsorption--desorption transition has been overlooked. Here we show the asymmetric role of elastic heterogeneity in the adsorption--desorption transition. We construct a minimal model incorporating adsorption-induced lattice expansion/contraction and an increase/decrease in the elastic moduli. We discover that the transition is hindered by the entropic and energetic effects which become asymmetric in adsorption process and desorption process, leading to the strong hysteretic nature of the transition. Furthermore, the adsorbed/desorbed sites exhibit spatially heterogeneous domain formation, implying that the domain morphology and interfacial area between adsorbed/desorbed sites can be controlled by elastic heterogeneity. Our results provide a theoretical guideline for designing soft porous crystals with tunable adsorption hysteresis and the dispersion and domain morphology of adsorbates using elastic heterogeneity.
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