Shi Xiansong, Wang Lei, Yan Nina, Wang Zhaogen, Guo Leiming, Steinhart Martin, Wang Yong
State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing, Jiangsu 211816, P.R. China.
Institut für Chemie neuer Materialien, Universität Osnabrück, Barbarastr. 7, 49069 Osnabrück, Germany.
Innovation (Camb). 2021 Feb 6;2(1):100088. doi: 10.1016/j.xinn.2021.100088. eCollection 2021 Feb 28.
Thin polymer coatings covering on porous substrates are a common composite structure required in numerous applications, including membrane separation, and there is a strong need to push the coating thicknesses down to the nanometer scale to maximize the performances. However, producing such ultrathin polymer coatings in a facile and efficient way remains a big challenge. Here, uniform ultrathin polymer covering films (UPCFs) are realized by a facile and general approach based on rapid solvent evaporation. By fast evaporating dilute polymer solutions spread on the surface of porous substrates, we obtain ultrathin coatings (down to ∼30 nm) exclusively on the top surface of porous substrates, forming UPCFs with a block copolymer of polystyrene--poly(2-vinyl pyridine) at room temperature or a homopolymer of poly(vinyl alcohol) (PVA) at elevated temperatures. Upon selective swelling of the block copolymer and crosslinking of PVA, we obtain highly permeable membranes delivering ∼2-10 times higher permeance in ultrafiltration and pervaporation than state-of-the-art membranes with comparable selectivities. We have invented a very convenient but highly efficient process for the direct preparation of defective-free ultrathin coatings on porous substrates, which is extremely desired in different fields in addition to membrane separation.
覆盖在多孔基材上的聚合物薄涂层是包括膜分离在内的众多应用中所需的常见复合结构，并且迫切需要将涂层厚度降低到纳米尺度以最大化性能。然而，以简便高效的方式制备这种超薄聚合物涂层仍然是一个巨大的挑战。在此，通过基于快速溶剂蒸发的简便通用方法实现了均匀的超薄聚合物覆盖膜（UPCFs）。通过快速蒸发铺展在多孔基材表面的稀聚合物溶液，我们仅在多孔基材的顶表面获得超薄涂层（低至约30纳米），在室温下用聚苯乙烯 - 聚（2 - 乙烯基吡啶）的嵌段共聚物或在高温下用聚乙烯醇（PVA）的均聚物形成UPCFs。通过对嵌段共聚物进行选择性溶胀和对PVA进行交联，我们获得了高渗透性的膜，其在超滤和渗透蒸发中的渗透通量比具有可比选择性的现有技术膜高约2 - 10倍。我们发明了一种非常方便但高效的方法，用于在多孔基材上直接制备无缺陷的超薄涂层，这在除膜分离之外的不同领域中也是极其需要的。
