螺旋聚异腈分子刷的可控合成及手性传递和放大研究

聚异腈是一种典型的螺旋高分子，其主链由碳-碳单键构成，每个主链碳原子上都有取代基。本项目中，我们拟设计合成含有异腈端基的高分子作为异腈大单体，利用我们发展的炔钯催化剂引发大单体的端基异腈活性聚合，制备高接枝密度的螺旋聚异腈分子刷。这种聚合物刷的每个主链原子上都接枝有高分子侧链，具有较高的接枝密度。通过这种合成方法的建立，我们拟利用炔钯催化剂引发嵌段结构的异腈大单体活性聚合，制备核-壳聚异腈分子刷；利用炔钯催化剂顺序引发两种或多种异腈大单体嵌段共聚，制备嵌段聚异腈分子刷。拟通过异腈大单体与小分子异腈共聚，利用小分子作为稀释剂来调控聚异腈分子刷的接枝密度，从而有望实现对其接枝密度和侧链分布的有效调控。此外，我们还拟研究手性异腈大单体聚合过程中的手性传递和放大效应，揭示手性传递和放大的基本规律。本项目的研究工作将为高分子科学领域发展新的螺旋高分子和高接枝密度的聚合物刷及其可控合成方法。

Polyisocyanide is a typical kind of helical polymer, whose backbone is consisted of C-C single bonds and bearing substituent on every backbone atom. In this proposal, we will design and synthesize a series of isocyanide end-functionalized polymers as macromonomers. Living/controlled polymerization of these macromonomers by highly active alkyne-Pd(II) catalyst will lead to the formation of helical polyisocyanide bottlebrushes. Such polymer brushes have extremely high grafting density because the polymeric side chain is grafted on every backbone atom. Taking advantage of this strategy, we will study the controlled polymerization of isocyanide end-functionalized block copolymers by the Pd(II) catalyst to produce core-shell polyisocyanide brushes. We will also investigate block copolymerization of two or more different kinds of isocyanide macromonomers to generate block polyisocyanide brushes. Moreover, copolymerization of isocyanide macromonomer with isocyanide small monomer as diluent will lead to the control over the grafting density. Thus the grafting density and the distribution of side chains can be readily tuned through the variation on the feed concentrations of the macromonomer and small monomer. Lastly, we will investigate the chirality transfer and amplification during the living/controlled polymerizations of chiral isocyanide macromonomers, and attempt to disclose the general rules of the chirality transfer and amplification of the polymerization. Through these investigations, we intend to develop a series novel helical polymers and densely grafted polymer brushes, and establish their controlled synthesis methods.