Division of Environmental Science and Engineering, Faculty of Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117576, Singapore.
J Phys Chem B. 2010 Feb 25;114(7):2422-9. doi: 10.1021/jp908194g.
A major problem in membrane technology for applications such as wastewater treatment or desalination is often the loss of membrane permeability due to biofouling initiated from protein adsorption and biofilm formation on the membrane surface. In this study, we developed a relatively simple and yet versatile approach to prepare polypropylene (PP) membrane with highly effective non-biofouling performance. Copolymer brushes were grafted to the surface of PP membrane through UV-induced polymerization of two oppositely charged monomers, i.e., [2-(methacryloyloxy)ethyl]trimethylammonium chloride (TM) and 3-sulfopropyl methacrylate potassium salt (SA), with varying TM:SA molar ratios. Surface analysis with scanning electron microscope (SEM) clearly showed the grafted copolymer brushes on the membrane surfaces and that with X-ray photoelectron spectroscope (XPS) revealed a similar TM:SA ratio of the grafted copolymer brushes to that of the monomer solution used for the polymerization. Water contact angle measurements indicated that the hydrophilicity of the membrane surfaces was remarkably improved by the grafting of the TM/SA copolymer brushes, with the lowest water contact angle of 27 degrees being achieved at the TM:SA ratio of around 1:1. Experiments for antiprotein adsorption with bovine serum album (BSA) and lysozyme (LYZ) and antibiofilm formation with Escherichia coli (E. coli) demonstrated a great dependence of the membrane performance on the TM:SA ratios of the grafted copolymer brushes. It was found that the characteristics of the surface charges of the membrane surfaces played a very important role in the non-biofouling performance, and the membrane surface with balanced positive and negative charges showed the best non-biofouling performance for the proteins and bacteria tested in this study.
在膜技术应用中，如废水处理或海水淡化，一个主要问题通常是由于蛋白质吸附和生物膜在膜表面形成而导致的膜渗透性损失。在这项研究中，我们开发了一种相对简单但功能多样的方法，通过两种带相反电荷的单体，即[2-（甲基丙烯酰氧基）乙基]三甲基氯化铵（TM）和 3-磺丙基甲基丙烯酸酯钾盐（SA）的紫外光诱导聚合，在聚丙烯（PP）膜表面接枝共聚物刷，改变 TM:SA 的摩尔比。扫描电子显微镜（SEM）的表面分析清楚地显示了膜表面接枝的共聚物刷，X 射线光电子能谱（XPS）显示接枝共聚物刷的 TM:SA 比与用于聚合的单体溶液的 TM:SA 比相似。水接触角测量表明，共聚物刷的接枝显著提高了膜表面的亲水性，在 TM:SA 比约为 1:1 时，水接触角最低可达 27 度。用牛血清白蛋白（BSA）和溶菌酶（LYZ）进行抗蛋白质吸附实验，用大肠杆菌（E. coli）进行抗生物膜形成实验，结果表明膜性能对接枝共聚物刷的 TM:SA 比有很大的依赖性。结果发现，膜表面的表面电荷特性在非生物污染性能中起着非常重要的作用，并且表面带有正负电荷平衡的膜对本研究中测试的蛋白质和细菌表现出最佳的非生物污染性能。
