Intermediate water (IW) has been reported to play an important role in nonthrombogenicity of biomaterials. However, clear insights into the IW in the hydrated polymer are still debated. In this study, a series of molecular dynamics simulations was performed to identify the IW structure in hydrated poly(ω-methoxyalkyl acrylate)s (PMCxAs, where x indicates the number of methylene carbons) with x = 1–6. Through the quantitative comparison with experimental measurements, IW molecules were suggested to mainly come from the water interacting with an oxygen atom of the polymers, while most of the nonfreezing water (NFW) molecules corresponded to the water interacting with two polymer oxygen atoms. In addition, the IW molecules were found to effectively enhance the flexibility of the PMCxA side chains in comparison with the NFW molecules. The variations of the saturated IW content and the side-chain flexibility with the methylene carbon chain length of PMCxA were also found to be correlated with the experimental nonthrombogenicity of PMCxA, suggesting that the polymer with the more saturated IW content and higher chain flexibility possesses better nonthrombogenicity. Furthermore, through the analyses of the interplays between the IW and polymer and between IW and its adjacent water, we found that the presence of the unique interaction between IW and its adjacent water in the hydrated poly(2-methoxyethyl acrylate) (PMEA) is the main factor causing different cold crystallization behaviors of PMEA from the other PMCxAs rather than the interaction between water and the PMCxA matrix. The findings will be useful in the development of new nonthrombogenic materials.

中文翻译：

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通过分子动力学模拟和差示扫描量热法测定阐明水合聚丙烯酸ω-甲氧基烷基酯中的中间水特征

据报道，中间水（IW）在生物材料的非血栓形成性中起着重要作用。但是，关于水合聚合物中内含子的清晰见解仍在争论中。在这项研究中，进行了一系列分子动力学模拟，以鉴定水合聚（ω-甲氧基烷基丙烯酸酯）（PMC x As，其中x表示亚甲基碳数）中的IW结构，其中x= 1–6。通过与实验测量结果的定量比较，表明IW分子主要来自与聚合物氧原子相互作用的水，而大多数非冷冻水（NFW）分子对应于与两个聚合物氧原子相互作用的水。另外，与NFW分子相比，发现IW分子可有效增强PMC x A侧链的柔性。饱和IW内容以及与PMC中的亚甲基碳链长度侧链灵活性的变化X甲还发现与PMC的实验nonthrombogenicity相关联XA，表明具有更高饱和IW含量和更高链柔性的聚合物具有更好的非血栓形成性。此外，通过分析IW与聚合物之间以及IW与相邻水之间的相互作用，我们发现水合聚丙烯酸2-（甲氧基乙酯）（PMEA）中IW与相邻水之间存在独特的相互作用是造成PMEA与其他PMC x As不同的冷结晶行为的主要因素，而不是水与PMC x A基质之间的相互作用。这些发现将对新的非血栓形成材料的开发有用。