二氧化碳响应性嵌段共聚物均孔膜的研究

Homoporous membranes derived from block copolymers (BCPs) can realize high-resolution separation with high efficiency. However, homoporous membranes with pore diameter smaller than 10 nm are difficultly prepared due to the mechanism of pore formation, which seriously limits their application in some important fields like biological macromolecules separation and classification. In this project, we propose to use BCPs that contain amino groups as raw materials and fabricate CO2-responsive homoporous membranes, aiming to endow the BCP membranes with intelligent property of CO2 response and acquire well-ordered pores below 10 nm for the use of precise separation of biological macromolecules. We will design and synthesize BCPs with minority block containing amine groups, and induce the perpendicular alignment of block copolymers by solvent annealing. After selective swelling induced pore formation, amino-contained chains would line along the pore walls, resulting in the block copolymers membranes with CO2-stimuli responsiveness. During separation process, CO2 can be introduced to change the protonation degree of CO2-responsive chains, regulate the stretching state of their conformation, and push down the pore diameter to sub-10 nm magnitude, so as to realize the precise separation of macromolecules such as proteins and polypeptides. Scientific issues including phase separation and perpendicular alignment behavior of BCPs, the influence of CO2 on membrane characteristics and the separation process of biomacromolecules under the action of CO2 will be studied in depth, in order to promote rational design of BCP homoporous membranes for process-oriented application and their application in biomacromolecular precise screening.

新近发展起来的嵌段共聚物均孔膜，可实现高效精密分离。但由于成孔机理的原因，难于获得孔径小于10nm的小孔径均孔膜，限制了它们在生物大分子分离等重要领域的应用。本项目提出以含氨基结构单元的嵌段共聚物为成膜基材，制备CO2活性均孔膜的思路，以赋予嵌段共聚物均孔膜CO2响应的智能特性，并获得10 nm以下的有效孔径，用于生物大分子的精密分离。拟设计、合成含氨基嵌段为分散相的嵌段共聚物，通过退火垂直取向，再经选择性溶胀成孔，获得含氨基嵌段富集于孔壁的均孔膜。在分离过程中，引入CO2，改变含氨基链段的质子化程度，调控其构象的伸展状态，将有效孔径调控下限推进至10nm以下，实现蛋白质、多肽等的精密分离。将深入研究共聚物相分离行为及垂直取向方法、CO2对膜孔特性的影响规律以及生物大分子在CO2作用下的膜分离过程等科学问题，以推动嵌段共聚物均孔膜面向应用过程的理性设计及其在生物大分子精密筛分中的应用。

嵌段共聚物分离膜具有孔径分布窄、孔道结构规整的特性，可实现高效精密分离。但由于成孔机理的原因，难于获得孔径小于10 nm的分离膜，限制了它们在生物大分子分离等重要领域的应用。本项目以含叔胺官能团的嵌段共聚物为成膜基材，制备CO2活性分离膜的，利用CO2响应性调控链段构象的伸展状态，以获得10 nm以下的有效孔径。建立了含有CO2响应基团的嵌段共聚物的合成方法，通过控制投料比调节两嵌段质量比，确定了适用于选择性溶胀成孔方法的嵌段共聚物原料的合成条件；以含有CO2响应基团的嵌段共聚物为制膜材料，基于嵌段共聚物的选择性溶胀成孔行为，建立了孔径分布较窄的CO2智能分离膜制备新方法；阐明了CO2与膜孔壁的相互作用及其调控膜分离性能的机理；利用CO2刺激下膜表面和孔壁链段质子化后伸展的特性，缩小膜孔径，成功将嵌段共聚物膜的有效孔径调控推进至5 nm以下，实现了对蛋白质、多肽等生物分子的高效筛分，推动嵌段共聚物膜面向应用过程的理性设计及其在生物大分子精密筛分中的应用。本项目研究成果在J. Membr. Sci.，Macromolecules等期刊发表SCI收录论文5篇，申请中国发明专利4件，其中已授权2件，申请PCT专利2件。