具有高度排它性自组装行为的单链Janus粒子的合成、纯化及应用探索

In this project, the two blocks of a diblock copolymer will be cross-linked, respectively, in the dilute solution. The resultant mixture solution contains multi-chain particles, single-chain irregular particles and regular single-chain Janus particles (RSCJPs). It is imaginable that the structural parameters of the RSCJPs in the mixture depend on the structural parameters of the diblock copolymer precursor. Then, we will carry out self-assembly of the polymeric particles mixture system. The core concept of this project is to deliberately control the conditions for the self-assembly so that the RSCJPs in the mixture system can undergo highly exclusive self-assembly, like recrystallization of small molecules, to form large size assemblies that can be separated from the system. Based on such exclusive self-assembly, pure RSCJPs can be obtained, and the size and composition of the particles can be precisely controlled. Furthermore, the application of RSCJPs in the construction of Janus ultrathin films will be explored. The core concept of this project has been confirmed in our preliminary research work, which proves the feasibility of this project..This recrystallization-like self-assembly behavior of synthetic polymers has not been reported. The preparation of pure RSCJPs has also not been reported; the size of the RSCJPs is in the range of a few to a dozen of nanometers, which is difficult to prepare by the existing methods. Therefore, by completion of this project, we will make important contributions to the fields of preparation of single-chain particles, macromolecular self-assembly, and preparation and self-assembly of Janus particles.

本项目拟从两嵌段共聚物出发，在其稀溶液中分别交联其两个嵌段，得到含有多链粒子、单链不规则粒子以及规则单链Janus粒子的混合物溶液；可以想象，混合物中规则单链Janus粒子的结构参数依赖于嵌段共聚物的结构参数。再实施混合体系的自组装。本项目的核心构想是控制条件，使得混合体系中的规整单链Janus粒子能够像小分子重结晶那样进行高度排它性的自组装，形成可从体系中分离的大尺寸组装体。在此基础上，制备出高纯度规整单链Janus粒子，实现其尺寸和组成的调控，探索其应用。本项目的核心构想已在初步的先期工作中得到证实，证明了本项目的可行性。.这种类似于重结晶的合成聚合物自组装行为未见报导。高纯度规整单链Janus粒子的制备也未见报导；现有方法难以制备几到十几纳米大小的高纯度规整单链Janus粒子。因此，本项目的完成将能为单链粒子制备、大分子自组装以及Janus粒子的制备与组装等领域的发展做出贡献。

本项目的研究目标为：１.由两嵌段共聚物构造单链Janus粒子，实现其高度排它性自组装；２.基于排它性自组装实现单链Janus粒子的纯化，制备出纯净的单链Janus粒子并控制其结构参数；3. 从规整的单链 Janus 粒子出发，利用LB膜技术对超薄Janus膜的制备与应用进行探索性研究。该项目所取得的成果如下：1.制备了不同结构参数的两嵌段均可交联的两嵌段共聚物。在其共同溶剂中以及较高浓度下分别交联两个嵌段，得到由多链聚集体、不规整单链粒子、规整单链Janus粒子组成的混合物。在临界条件下，在两嵌段具有相近分子量的上述两嵌段共聚物体系中，混合物中高度规整的单链Janus粒子可发生类似于小分子重结晶那样的高度排它性自组装，并由于Janus粒子两侧体积相似使得内部为层状结构的组装体可达宏观尺寸。2.将宏观尺寸组装体从体系中捞出并溶解后得到纯净的规整单链Janus粒子，实现了单链Janus粒子的纯化。通过控制嵌段共聚物的结构参数，制备出了5种结构参数不同的纯净的单链Janus粒子。3.研究发现，LB膜技术难以实现上述纯净的单链Janus粒子在界面上的规整排列。因此，我们实施了蝌蚪状粒子在基底表面的可控密度均匀接枝，再利用蝌蚪状粒子“尾部”形成的外层超薄膜的厚度涨落，以及在基底表面吸附的粒子间的堆积孔，初步构造出超薄的Janus微孔膜。因此，我们成功实现了本项目的核心目标。同时，我们还成功扩展了排它性自组装的研究体系；由规整单链Janus粒子出发得到了极小周期层状结构；分别构建了具有可控分子链缠结、能够自我驱动可控解离、可在玻璃态下响应性碎裂的新颖结构与性能的大分子组装体。研究成果在ACS Macro Lett.（3篇）, Polym. Chem.（3篇）, Chem. Commun.等期刊上发表。有关排它性自组装的成果被选为ACS Editor's Choice；有关可控缠结组装体的构建与性能研究的成果被Polym. Chem.选为Hot article.