嵌段共聚物自组装均孔膜的仿生矿化及其功能化研究

The membrane technologies have been proved viable in water purification and other similar applications, including desalination, dialysis, sterile filtration and so on. Isoporous membrane, which was prepared from block copolymer, attracted the attention of the researchers in recent years. The narrow pore size distribution of isoporous membrane provides a high selectivity, and the non-tortuous channel of isoporous membrane ensures a high permeability in the process of filtration. In this project, the method of preparing the large area isoporous membrane by block copolymer is studied. Then, a “functional matrix” isoporous membrane was fabricated by a block copolymer of poly(4-vinylcatechol acetonide)-block-polylactide (P4VCA-b-PLA). Specially, the block of P4VCA was bioinspired from biomimetic molecule of dopamine. According the annealing process, the P4VCA block formed the matrix phase of the membrane and the PLA block formed the cylinder phase of the membrane. After the deprotection step, the catechol function groups were exposed on the surface: through the interaction of catechol and zirconium sulfate to realize the mineralization of the membrane; through the strong coordination between the catechol and metal ions, loading the FeOOH nanorod, to realize the photocatalysis of membrane; and through the reaction between catechol and boric acid group, grafting the stimuli responsive polymer on the membrane surface, to realize the smart control of the isoporous membrane.

膜法水处理是一种环保、节能、高效的水处理方式，而均孔膜以其高选择性、高通量引起了科研工作者的重点关注。以嵌段共聚物自组装结构为模板制备均孔膜是一种新兴的制备方法，但存在难以大面积制备以及功能化困难等缺点。在本课题的研究中，将首先探索改善大面积制备高性能嵌段共聚物均孔膜的方法；而后，通过合成4-乙烯基邻苯二酚缩丙酮-丙交酯嵌段共聚物，将仿生基团引入均孔膜的基底中，制备出基底可功能化的均孔膜，进而实现均孔膜的表面矿化、光催化以及智能化，为嵌段共聚物均孔膜的功能化提供一种新途径。实验设计中，在移除缩丙酮保护基团后，可以得到邻苯二酚裸露的均孔膜表面：通过邻苯二酚与硫酸锆水解的相互作用完成均孔膜的表面矿化，实现均孔膜表面亲疏水性的调控；通过邻苯二酚与金属离子的强配位完成其对氢氧化氧化铁的负载，实现均孔膜的光催化；以及通过邻苯二酚与硼酸的特征反应完成其对刺激响应性高分子的接枝，实现均孔膜的智能化。

膜法水处理是一种环保、节能且高效的水处理方式。在水处理膜中，均孔膜以其高选择性、高通量等特性引起了科研工作者的重点关注。本研究利用嵌段共聚物的自组装特性制备均孔膜，以易降解高分子为牺牲嵌段，并将邻苯二酚结构引入保留嵌段，为均孔膜的功能化提供了条件。在研究期内，完成了单体的合成、嵌段共聚物的设计与合成、嵌段共聚物自组装结构的筛选、复合膜的组装、嵌段共聚物牺牲相的移除、均孔膜的矿化、矿化均孔膜的过滤性能、基于邻苯二酚结构的功能化等预设实验方案。通过对制膜方式的研究，探讨了改善大面积制备柔性嵌段共聚物均孔膜的可能性，并通过改变嵌段共聚物均孔膜表面的亲疏水性解决了过膜压力大、膜污染严重等问题。但由于研究难度较大以及预设方案的不确定性，项目组并未完全实现预设的技术要求。另外，为拓展研究方向，引入氧化石墨烯作为膜功能化的中间体，成功开发了一种新的石墨烯薄膜制备方法，且相关研究仍在推进中。