Schmidt Martin, Zahn Stefan, Gehlhaar Florian, Prager Andrea, Griebel Jan, Kahnt Axel, Knolle Wolfgang, Konieczny Robert, Gläser Roger, Schulze Agnes
Leibniz Institute of Surface Engineering (IOM), Permoserstr. 15, 04318 Leipzig, Germany.
Institute of Chemical Technology, Leipzig University, Linnéstraße 3, 04103 Leipzig, Germany.
Polymers (Basel). 2021 Jun 2;13(11):1849. doi: 10.3390/polym13111849.
Radiation-induced graft immobilization (RIGI) is a novel method for the covalent binding of substances on polymeric materials without the use of additional chemicals. In contrast to the well-known radiation-induced graft polymerization (RIGP), RIGI can use non-vinyl compounds such as small and large functional molecules, hydrophilic polymers, or even enzymes. In a one-step electron-beam-based process, immobilization can be performed in a clean, fast, and continuous operation mode, as required for industrial applications. This study proposes a reaction mechanism using polyvinylidene fluoride (PVDF) and two small model molecules, glycine and taurine, in aqueous solution. Covalent coupling of single molecules is achieved by radical recombination and alkene addition reactions, with water radiolysis playing a crucial role in the formation of reactive solute species. Hydroxyl radicals contribute mainly to the immobilization, while solvated electrons and hydrogen radicals play a minor role. Release of fluoride is mainly induced by direct ionization of the polymer and supported by water. Hydrophobic chains attached to cations appear to enhance the covalent attachment of solutes to the polymer surface. Computational work is complemented by experimental studies, including X-ray photoelectron spectroscopy (XPS) and fluoride high-performance ion chromatography (HPIC).
辐射诱导的接枝固定化（RIGI）是一种在不使用额外化学物质的情况下将物质共价结合到聚合物材料上的新方法。与著名的辐射诱导接枝聚合（RIGP）不同，RIGI可以使用非乙烯基化合物，如小分子和大分子功能分子、亲水性聚合物，甚至酶。在基于电子束的一步法过程中，可以按照工业应用的要求，以清洁、快速和连续的操作模式进行固定化。本研究提出了一种在水溶液中使用聚偏氟乙烯（PVDF）和两种小分子模型物质甘氨酸和牛磺酸的反应机理。单分子的共价偶联通过自由基重组和烯烃加成反应实现，水的辐射分解在活性溶质物种的形成中起关键作用。羟基自由基主要促成固定化，而溶剂化电子和氢自由基起次要作用。氟化物的释放主要由聚合物的直接电离引起，并得到水的支持。附着在阳离子上的疏水链似乎增强了溶质与聚合物表面的共价结合。计算工作得到了包括X射线光电子能谱（XPS）和氟化物高效离子色谱（HPIC）在内的实验研究的补充。
