全氟乙烯基醚类单体的自由基共聚合、基于“SuFEx”点击反应的后修饰及其性能

Free-Radical Copolymerization of Perfluorinated Vinyl Ether,Post-Modification by“SuFEx”Click Reaction and Properties

首先在常压和非氟溶剂中通过自由基热引发共聚合制备了6种全氟乙烯基醚类单体与非氟乙烯基醚类单体的共聚物,然后经“SuFEx”点击反应进行功能化修饰制得聚合物分子刷,进一步通过透析法构筑高含氟量的聚合物纳米粒子。利用傅里叶变换红外光谱(FT-IR)、核磁共振氟谱(^(19)F-NMR)、核磁共振氢谱(^(1)H-NMR)差示扫描量热分析(DSC)和凝胶渗透色谱(GPC)等详细表征了含氟聚合物的结构、接枝率及物化性能,证明全氟乙烯基醚类单体与非氟乙烯基醚类单体共聚合得到交替共聚物,与乙酸乙烯酯单体共聚合得到无规共聚物。同时“SuFEx”点击反应可以实现磺酰氟(―SO_(2)F)共聚物侧链的高效接枝。紫外-可见分光光度计(UV-Vis)、动态光散射(DLS)和透射电镜(TEM)分析表明,两亲性氟化共聚物自组装形成了流体力学粒径120 nm左右的球形胶束状聚集体,且具有较低的临界聚集浓度。

Six kinds of perfluorinated vinyl ether-based copolymers were synthesized by thermal radical polymerization under normal atmospheric pressure and in nonfluorinated solvents.The“SuFEx”click reaction was used to conjugate with amine-terminated small molecules or polyethylene glycol(PEG)to form the graft copolymer or the polymer brush,and the related polymeric nanoparticles with high fluorine content were fabricated by aqueous self-assembly.The structure,molecular weight and glass transition temperature of the fluorinated copolymers were tested by nuclear magnetic resonance spectroscopy(^(1)H-NMR,^(19)F-NMR),Fourier-transform infrared spectroscopy(FT-IR),gel permeation chromatography(GPC)and differential scanning calorimetry (DSC). The results confirm the structures of those copolymers, and the copolymerization of perfluorinated vinyl ether with their nonfluorinated counterparts produce alternative copolymers compared to random copolymers from that copolymerization with vinyl acetate. Those copolymers containing sulfonyl fluoride group (―SO_(2)F) can be further grafted with amine-containing molecules with high efficiency by “SuFEx” reaction, and the micellar nanoparticles with high fluorine content, low critical aggregation concentration, and uniform size can be self-assembled in aqueous solution. Results of ultraviolet-visible spectroscopy(UV-Vis), dynamic light scattering (DLS) , transmission electron microscopy (TEM) indicate that fluorinated copolymers can self-assemble to form micelle like nanoparticles with a hydrodynamic diameter of about 120 nm as well as has low critical aggregation concentration. This work provides a simple method to synthesize fluorinated copolymers with high fluorine content that can be effectively modified by the “SuFEx” click reaction.