Gukelberger Ephraim, Hitzel Christian, Mancuso Raffaella, Galiano Francesco, Bruno Mauro Daniel Luigi, Simonutti Roberto, Gabriele Bartolo, Figoli Alberto, Hoinkis Jan
Laboratory of Industrial and Synthetic Organic Chemistry (LISOC), Department of Chemistry and Chemical Technologies, University of Calabria, 87036 Rende (CS), Italy.
Center of Applied Research (CAR), Karlsruhe University of Applied Sciences, 76133 Karlsruhe, Germany.
Membranes (Basel). 2020 Sep 21;10(9):246. doi: 10.3390/membranes10090246.
Membrane modification is becoming ever more relevant for mitigating fouling phenomena within wastewater treatment applications. Past research included a novel low-fouling coating using polymerizable bicontinuous microemulsion (PBM) induced by UV-LED polymerization. This additional cover layer deteriorated the filtration capacity significantly, potentially due to the observed high pore intrusion of the liquid PBM prior to the casting process. Therefore, this work addressed an innovative experimental protocol for controlling the viscosity of polymerizable bicontinuous microemulsions (PBM) before casting on commercial ultrafiltration (UF) membranes. Prior to the coating procedure, the PBM viscosity modulation was carried out by controlled radical polymerization (CRP). The regulation was conducted by introducing the radical inhibitor 2,2,6,6-tetramethylpiperidine 1-oxyl after a certain time (CRP time). The ensuing controlled radical polymerized PBM (CRP-PBM) showed a higher viscosity than the original unpolymerized PBM, as confirmed by rheological measurements. Nevertheless, the resulting CRP-PBM-cast membranes had a lower permeability in water filtration experiments despite a higher viscosity and potentially lower pore intrusion. This result is due to different polymeric structures of the differently polymerized PBM, as confirmed by solid-state nuclear magnetic resonance (NMR) investigations. The findings can be useful for future developments in the membrane science field for production of specific membrane-coating layers for diverse applications.
膜改性对于减轻废水处理应用中的污染现象变得越来越重要。过去的研究包括一种使用紫外线发光二极管聚合诱导的可聚合双连续微乳液（PBM）的新型低污染涂层。这种额外的覆盖层显著降低了过滤能力，这可能是由于在浇铸过程之前观察到液体PBM的高孔隙侵入。因此，这项工作提出了一种创新的实验方案，用于在商业超滤（UF）膜上浇铸之前控制可聚合双连续微乳液（PBM）的粘度。在涂覆程序之前，通过可控自由基聚合（CRP）对PBM的粘度进行调节。调节是在一定时间（CRP时间）后引入自由基抑制剂2,2,6,6-四甲基哌啶1-氧基来进行的。流变学测量证实，随后得到的可控自由基聚合PBM（CRP-PBM）的粘度高于原始未聚合的PBM。然而，尽管粘度较高且潜在的孔隙侵入较低，但在水过滤实验中，所得的CRP-PBM浇铸膜的渗透率较低。固态核磁共振（NMR）研究证实，这一结果是由于不同聚合程度的PBM具有不同的聚合物结构。这些发现对于膜科学领域未来开发用于各种应用的特定膜涂层的发展可能是有用的。
