Abstract Carbon molecular sieve (CMS) membranes are a special class of nanoporous membranes with angstrom-level molecular discrimination properties, which make them appealing for separating a wide spectrum of gas-pairs. The mechanism of pyrolysis by which a polymer coil is transformed into these rigid sieves is complex; however, we present a framework that can explain this transformation. Representative polymer precursors and pyrolysis conditions are discussed that yield attractive CMS membrane separation performance for extremely challenging gas pairs. Control of penetrant motions in the diffusion activated state, reflected in the entropy of activation of subtly different penetrants, enables the attractive diffusion selectivity of such membranes. This control, virtually absent even in rigid state-of-the-art polymeric membranes, makes CMS materials extraordinarily attractive. Moreover, unlike other rigid sieving materials, CMS membranes have the added advantage of being processable into highly productive, flexible hollow fibers with good mechanical properties and long-term stability under constant gas feeds. In this article, we also identify some key areas of CMS which would greatly benefit from expertise from other fields like computation or materials characterization that can potentially complement transport-based studies.

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下一代膜——使用定制的碳

摘要 碳分子筛（CMS）膜是一类特殊的纳米多孔膜，具有埃级分子辨别特性，这使得它们对分离广谱的气体对具有吸引力。将聚合物线圈转化为这些刚性筛网的热解机制很复杂。然而，我们提出了一个可以解释这种转变的框架。讨论了代表性聚合物前体和热解条件，这些条件为极具挑战性的气体对产生有吸引力的 CMS 膜分离性能。在扩散激活状态下对渗透运动的控制，反映在细微不同渗透剂的激活熵中，使这种膜具有吸引力的扩散选择性。这种控制，即使在最先进的刚性聚合物膜中也几乎不存在，使 CMS 材料格外有吸引力。此外，与其他刚性筛分材料不同，CMS 膜具有可加工成高产、柔性中空纤维的额外优势，在恒定气体进料下具有良好的机械性能和长期稳定性。在本文中，我们还确定了 CMS 的一些关键领域，这些领域将极大地受益于其他领域的专业知识，如计算或材料表征，这些领域可以潜在地补充基于传输的研究。