MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, and ‡Key Laboratory of Adsorption and Separation Materials and Technologies of Zhejiang Province, Zhejiang University , Hangzhou 310027, China.
Langmuir. 2017 Jul 25;33(29):7298-7304. doi: 10.1021/acs.langmuir.7b01681. Epub 2017 Jul 10.
Poly(oligoethylene glycol methacrylate) (POEGMA) and zwitterionic polymer brushes have been widely used for constructing biocompatible or antifouling surfaces, and their oxidative stability is very important to the practical application. Herein, POEGMA, poly(sulfobetaine methacrylate) (PSBMA), poly(2-(methacryloyloxy)ethyl phosphorylcholine) (PMPC), and poly(carboxybetaine methacrylate) (PCBMA) were grafted on quartz crystal microbalance (QCM) chips via surface-initiated atom transfer radical polymerization (SI-ATRP). XPS and MS analyses demonstrate that the mass loss of these polymer brushes in oxidative environment is due to the scission of the polymer-anchoring segments. Molecular simulation further illustrates this mass loss mechanism should be always true for those polymer brushes anchored on different substrates. In situ QCM monitoring indicates that, compared with zwitterionic polymethacrylates, POEGMA brushes show the lowest mass loss rate mainly due to their cross-linked structures. This study sheds light on the contradictory reports about the oxidative stability of POEGMA and zwitterionic polymethacrylate brushes up to now, and highlights the important role of the polymer-anchoring segments playing in the oxidative stability of polymer brushes.
聚（聚乙二醇甲基丙烯酸酯）（POEGMA）和两性离子聚合物刷已广泛用于构建生物相容性或抗污表面，其氧化稳定性对于实际应用非常重要。本文通过表面引发原子转移自由基聚合（SI-ATRP）将 POEGMA、聚（磺酸甜菜碱甲基丙烯酸酯）（PSBMA）、聚（2-（甲基丙烯酰氧基）乙基磷酸胆碱）（PMPC）和聚（羧酸甜菜碱甲基丙烯酸酯）（PCBMA）接枝到石英晶体微天平（QCM）芯片上。XPS 和 MS 分析表明，这些聚合物刷在氧化环境中的质量损失是由于聚合物锚固段的断裂所致。分子模拟进一步说明了这种质量损失机制对于锚固在不同基底上的聚合物刷应该始终是正确的。原位 QCM 监测表明，与两性离子聚甲基丙烯酸酯相比，POEGMA 刷显示出最低的质量损失率，主要归因于其交联结构。这项研究阐明了迄今为止关于 POEGMA 和两性离子聚甲基丙烯酸酯刷的氧化稳定性的矛盾报告，并强调了聚合物锚固段在聚合物刷的氧化稳定性中所起的重要作用。
