Olowookere Feranmi V, Shah Vrajkumar, Weinman Steven T, Turner C Heath
Department of Chemical and Biological Engineering, The University of Alabama, Tuscaloosa, Alabama 35487-0203, United States.
ACS Appl Mater Interfaces. 2025 Aug 20;17(33):47659-47671. doi: 10.1021/acsami.5c08791. Epub 2025 Aug 5.
Most thin-film composite reverse osmosis (RO) membranes are formed via interfacial polymerization (IP) between -phenylenediamine (MPD) and trimesoyl chloride (TMC), yet controlling their structure and selectivity remains challenging. Surfactants can regulate this process, highlighting the need to understand the factors behind MPD transport and its interactions with surfactants. In this study, we provide a detailed molecular-level analysis by first conducting electronic structure calculations to investigate 17 surfactant/counterion combinations. Based on binding energies and partition coefficients, we select four surfactants for further interfacial MD simulations and eventually examine two surfactants in TMC-MPD cross-linking simulations, followed by structural characterization of the polymer membranes. Our results identify key molecular factors influencing membrane synthesis: electrostatic interactions (which affect surfactant binding energy with MPD and their orientation) and MPD partitioning into the organic phase (which impacts its stability at the interface). These factors dictate void connectivity through the membrane and may influence membrane performance, e.g., water permeance.
大多数薄膜复合反渗透（RO）膜是通过间苯二胺（MPD）和均苯三甲酰氯（TMC）之间的界面聚合（IP）形成的，但控制它们的结构和选择性仍然具有挑战性。表面活性剂可以调节这一过程，这凸显了了解MPD传输背后的因素及其与表面活性剂相互作用的必要性。在本研究中，我们首先通过进行电子结构计算来研究17种表面活性剂/抗衡离子组合，从而提供详细的分子水平分析。基于结合能和分配系数，我们选择了四种表面活性剂进行进一步的界面分子动力学模拟，并最终在TMC-MPD交联模拟中研究了两种表面活性剂，随后对聚合物膜进行了结构表征。我们的结果确定了影响膜合成的关键分子因素：静电相互作用（影响表面活性剂与MPD的结合能及其取向）和MPD在有机相中的分配（影响其在界面处的稳定性）。这些因素决定了贯穿膜的孔隙连通性，并可能影响膜的性能，例如水渗透通量。
