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arXiv 2402.07830cond-mat.softphysics.chem-ph
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从异质能量景观角度解释膜渗透的有效能量势垒

Interpreting effective energy barriers to membrane permeation in terms of a heterogeneous energy landscape

Nathanael S. Schwindt, Mor Avidar, Razi Epsztein, Anthony P. Straub, Michael R. Shirts

AI总结:

该研究将过渡态理论扩展至包含膜自由能势垒分布,揭示最可渗透路径上的最高势垒主导实验观测到的有效势垒,并指出忽略膜异质性会导致对输运机制的错误解释。

摘要:

近年来,主要研究工作一直致力于理解聚合物膜中的分子输运,特别是反渗透膜和纳滤膜。过渡态理论是一种日益常用的方法,用于在分子细节层面探索跨膜渗透机制,但大多数应用将膜内所有输运自由能势垒视为相等。这一假设忽略了聚合物膜固有的结构和化学异质性。在本工作中,我们扩展了过渡态理论框架,以纳入膜自由能势垒的分布。我们表明,沿最可渗透路径的最高自由能势垒,而非典型路径上的势垒,对实验观测到的有效自由能势垒贡献最大。我们表明,即使是分子势垒中中等程度的随机异质性,也会显著影响我们对膜输运机制的解释。对实验测得势垒的简化解释可能导致对控制输运的潜在机制产生错误假设,并遗漏与整体渗透性最相关的机制。

英文摘要:

Major efforts in recent years have been directed towards understanding molecular transport in polymeric membranes, in particular reverse osmosis and nanofiltration membranes. Transition-state theory is an increasingly common approach to explore mechanisms of transmembrane permeation with molecular details, but most applications treat all free energy barriers to transport within the membrane as equal. This assumption neglects the inherent structural and chemical heterogeneity in polymeric membranes. In this work, we expand the transition-state theory framework to include distributions of membrane free energy barriers. We show that the highest free energy barriers along the most permeable paths, rather than typical paths, provide the largest contributions to the experimentally-observed effective free energy barrier. We show that even moderate, random heterogeneity in molecular barriers will significantly impact how we interpret the mechanisms of transport through membranes. Simplified interpretations of experimentally measured barriers can lead to incorrect assumptions about the underlying mechanisms governing transport and miss the mechanisms most relevant to the overall permeability.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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