超亲水/疏油型仿生自清洁共聚物材料的制备及其对PVDF膜抗污改性研究

Porous membrane surface fouling is the main bottleneck reventing its wide application in treating the wastewater and biological separation process. This propose is aimed to solving the serious surface fouling of the polymer ultrafiltration membrane during the industrial application. Based on the scientific understanding of anti-fouling phenomenon of the nature surface, the synergistic effect of nonfouling and fouling-release was proposed. And the superhydrophilic/oleophobic self-cleaning copolymer materials will be bioinspired synthesized and applied in surface modification of PVDF ultrafiltration membrane. The current work will focus on the molecular design and preparation of diblock copolymer with tailored structure by ATRP. A series of special diblcok copolymers with superhydrophilic/oleophobic performance would be prepared by fluorinated acrylate and nonionic/ionic hydrophilic monomers(CBMA/AM/PDMC/AA etc). In terms of the characterization of copolymers film and self-cleaning performance, the microstructure，chemical composition，molecular weight and distribution，surface segregation，wetting and absorption properties of the diblock copolymers will be investigated in deepside. The relationship of fouling with the ionic interactions, hydrogen-bond, morphology and wetting properties of surface will be established. The protein adsorption resistance and the anti-biofouling mechanism of the copolymer films surface will be revealed, and the novel ultrafiltration membrane materials with stable self-cleaning performance will be prepared. Then, we will explore the theoretical foundation to construct the new membrane materials with stable self-cleaning performance.

多孔膜表面污染是制约膜技术广泛应用于污水处理与生物分离等领域的瓶颈问题。本项目以解决PVDF膜表面污染问题为目标，基于对自然界生物表面防污机理的科学认识，提出超亲水抗污与污染释放的协同作用思想，构建超亲水/疏油型仿生自清洁嵌段共聚物材料，并对PVDF膜进行抗污改性。项目拟通过仿生设计和ATRP聚合方法实现对共聚物结构的精确控制，将离子型与非离子型超亲水链段，如羧酸甜菜碱聚合物(PCBMA)/聚丙烯酰胺(PAM)等引入到环境友好型含氟聚合物中，制备具有特定序列结构的嵌段共聚物。进而研究共聚物的表面微结构与表面物理化学性能，考察超亲水/疏油型共聚物的多尺度结构，如共聚物的化学组成、序列结构、带电形式、聚集态结构、表面偏析行为等与表面特殊浸润行为以及抗污性之间的相互关系，揭示有机污染物与材料表面的作用形式与吸附机理，构建持久稳定的自清洁抗污表面，为仿生制备高性能聚合物膜分离新材料提供理论依据。

多孔膜表面污染是制约膜技术广泛应用于污水处理领域的关键问题。本项目以解决超滤膜表面污染问题为目标，基于对表面防污机理的科学认识和仿生概念，提出超两亲多机制协同作用思想，构建超亲水/疏油型仿生自清洁嵌段共聚物材料，并对PVDF和PES超滤膜进行抗污改性。通过仿生设计和可控聚合方法实现对共聚物结构的精确控制，分别将离子型与非离子型超亲水链段，如羧酸甜菜碱聚合物(PCBMA)/聚丙烯酰胺(PAM)等引入到环境友好型含氟聚合物中，制备具有特定序列结构的嵌段共聚物，另外我们还合成了一系列具有具有超浸润性能的两亲性聚氨酯和仿贻贝共聚物材料。系统研究了各种超浸润共聚物的表面微结构与表面物理化学性能，考察超亲水/疏油型共聚物的多尺度结构，如共聚物的化学组成、序列结构、带电形式、聚集态结构、表面偏析行为等与表面特殊浸润行为以及抗污性之间的相互关系，揭示了各种有机污染物与材料表面的作用形式与吸附机理，构建出具有持久稳定的自清洁抗污表面。经两性离子型两亲含氟共聚物P(CBMA-co-TFOA)改性后的超滤膜可逆通量衰减降低到16.7%，不可逆通量衰减几乎为零，对应的总通量衰减指数为17.4%，通量恢复率高达99.3%。不同序列结构两亲共聚物的表面偏析能力为P(PEG-co-TFOA) < P(PEG-grad-TFOA) < P(PEG-b-TFOA)，两亲性嵌段共聚物在膜表面具有最高的迁移率，其抗污性能也最佳，可逆通量下降为16.6 %，不可逆通量下降到0.2 %，对应的总通量衰减为16.8 %，通量恢复率高达99.8%。研究结果为仿生制备高性能聚合物膜分离新材料提供了理论依据。