Polymer crystal hydrates (PCHs) are crystalline solids that form between a polymer and water. To date, only four distinct PCHs have been discovered—one of polyoxacyclobutane (POCB) and water, and three different polymorphs of polyethyleneimine (PEI) and water. These PCHs were first reported decades ago and have fascinating structures and peculiar properties that make them potentially useful for a wide range of applications including refrigeration, proton conduction membranes, and desalination. This perspective revisits what is known about these compounds, categorizes their similarities and differences with other known compounds, and offers a perspective into future efforts to discover new PCHs to address technological needs for society.

中文翻译：

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聚合物晶体水合物的迷人世界：概述


聚合物晶体水合物 (PCH) 是聚合物和水之间形成的结晶固体。迄今为止，仅发现了四种不同的 PCH：一种是聚氧杂环丁烷 (POCB) 和水，以及三种不同的聚乙烯亚胺 (PEI) 和水多晶型物。这些 PCH 于几十年前首次被报道，具有令人着迷的结构和独特的性质，使其具有广泛的应用潜力，包括制冷、质子传导膜和海水淡化。这一观点重新审视了这些化合物的已知情况，对它们与其他已知化合物的相似之处和差异进行了分类，并为未来发现新的 PCH 以满足社会技术需求的努力提供了视角。