Characterization of the internal morphology of thin film composite membranes used in reverse osmosis (RO) is a prerequisite for understanding the connection between microstructure and water transport properties and is necessary for the design of membranes with improved performance. Here, we examine a series of fully aromatic polyamide active layers of RO membranes that vary in crosslinking using a combination of resonant soft X-ray scattering (RSoXS), transmission electron microscopy (TEM), and atomic force microscopy (AFM). Analysis of RSoXS profiles reveals a correlation between membrane structure and crosslinking density. Through a combination of scattering contrast calculations, TEM, and AFM micrographs, we assign the dominant contribution to RSoXS data as either surface roughness or chemical heterogeneity, depending on the X-ray energy used. Altogether, our results demonstrate the utility of soft X-ray scattering to examine the microstructure of water filtration membranes.

中文翻译：

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利用共振软 X 射线散射探测聚酰胺薄膜复合膜的内部微观结构

表征用于反渗透 (RO) 的薄膜复合膜的内部形态是了解微结构与水传输性能之间联系的先决条件，也是设计具有改进性能的膜所必需的。在这里，我们使用共振软 X 射线散射 (RSoXS)、透射电子显微镜 (TEM) 和原子力显微镜 (AFM) 的组合检查了一系列完全芳香族聚酰胺活性层的 RO 膜，这些活性层在交联方面有所不同。RSoXS 曲线的分析揭示了膜结构和交联密度之间的相关性。通过结合散射对比度计算、TEM 和 AFM 显微照片，我们将 RSoXS 数据的主要贡献分配为表面粗糙度或化学异质性，具体取决于所使用的 X 射线能量。