Abstract Co-solvent assisted interfacial polymerization (CAIP) has been widely used to increase the water permeability of thin-film composite (TFC) reverse osmosis (RO) membranes. However, its outcomes are often poorly understood or unpredictable. To bridge the gap between conventional wisdom and the real effects of the co-solvent, we report—for the first time, to the best of our knowledge—empirical evidence in terms of the actual interfacial tension between two immiscible solutions used in CAIP. According to our results, dimethyl sulfoxide (DMSO), which is frequently used as a co-solvent, influences IP by interacting with trimesoyl chloride (TMC). The dipole-dipole interaction between DMSO and TMC was estimated to increase the TMC concentration at the interface and, thereby, the reaction rate. Due to the fast reaction, the diffusion barrier forms quickly, reducing the thickness and roughness of the active layer. The cross-linking degree was also determined to decrease due to the incomplete reaction that occurs when one of three acyl chloride groups interacts with Sδ+−Oδ− electrostatic dipoles of DMSO at the interface, as evidenced by the variation in unreacted acyl chloride groups in the active layer and by the nitrogen/oxygen ratio. Such morphological changes were consistent with the trend in the performances of the RO membranes prepared with different amounts of DMSO, and were used to interpret the possible transport phenomena.

中文翻译：

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全面了解共溶剂对界面聚合的影响：与均苯三甲酰氯的相互作用

摘要 共溶剂辅助界面聚合 (CAIP) 已被广泛用于提高薄膜复合 (TFC) 反渗透 (RO) 膜的透水性。然而，其结果往往鲜为人知或不可预测。为了弥合传统智慧与共溶剂的实际效果之间的差距，我们首次报告了 CAIP 中使用的两种不混溶溶液之间实际界面张力的经验证据。根据我们的结果，经常用作共溶剂的二甲基亚砜 (DMSO) 通过与均苯三甲酰氯 (TMC) 相互作用来影响 IP。据估计，DMSO 和 TMC 之间的偶极-偶极相互作用会增加界面处的 TMC 浓度，从而增加反应速率。由于反应快，扩散势垒迅速形成，降低了有源层的厚度和粗糙度。由于三个酰氯基团中的一个与界面处 DMSO 的 Sδ+-Oδ- 静电偶极相互作用时发生的不完全反应，交联度也被确定为降低，正如未反应的酰氯基团在界面上的变化所证明的那样。活性层和氮/氧比。这种形态变化与用不同量 DMSO 制备的 RO 膜的性能趋势一致，并用于解释可能的传输现象。由于三个酰氯基团中的一个与界面处 DMSO 的 Sδ+-Oδ- 静电偶极相互作用时发生的不完全反应，交联度也被确定为降低，正如未反应的酰氯基团在界面上的变化所证明的那样。活性层和氮/氧比。这种形态变化与用不同量 DMSO 制备的 RO 膜的性能趋势一致，并用于解释可能的传输现象。由于三个酰氯基团中的一个与界面处 DMSO 的 Sδ+-Oδ- 静电偶极相互作用时发生的不完全反应，交联度也被确定为降低，正如未反应的酰氯基团在界面上的变化所证明的那样。活性层和氮/氧比。这种形态变化与用不同量 DMSO 制备的 RO 膜的性能趋势一致，并用于解释可能的传输现象。