申请人首创的“两仪聚合”能在增长链两端分别进行阴离子聚合与阳离子聚合，且当单体耗尽时聚合链之间自发偶合反应，由连锁聚合转变为逐步聚合，从环状单体一步法直接合成多嵌段共聚物。本项目用稀土配合物为催化剂，以环酯/环醚/氨基酸-N-(硫代)羧酸酐等为单体，深入研究两仪聚合反应特征，明晰催化剂/单体/聚合条件之间的平衡关系，联用实验表征和密度泛函理论计算，揭示两仪聚合的微观反应机理。设计并实现多种稀土催化剂催化环状单体两仪聚合，合成具有多嵌段、环状、星形、（超）支化、柱状聚合物刷等复杂拓扑结构的聚酯/聚醚/聚氨基酸生物医用材料。本项目研究成果将建立全新的两仪聚合方法学，发展离子聚合与配位聚合理论，拓展稀土催化剂在聚合方面的应用。

“Janus polymerization”, firstly reported by the applicant, combines anionic and cationic polymerizations on the two ends of one propagating chain. Both ends carry out living polymerizations without the interference from each other. The growing chain ends perform coupling reactions only after the consumption of monomer(s), which converts chain-growth polymerization into step-growth polymerization. It is the only existing one-step method to produce multi-block copolymers directly from monomers. In this proposal, the applicant is going to use rare earth complexes to catalyze Janus polymerization of cyclic monomers including lactones, lactides, cyclic ethers, amino acid-N-(thio)carboxyanhydrides, etc. The project is to develop new catalytic and polymerization systems based on the balance between catalysts and monomers. The key point of the project is to investigate kinetics and mechanisms of Janus polymerization by means of both experimental characterizations and calculations of density functional theory. Deep understanding and more examples of Janus polymerizations lead to novel synthetic approaches to synthesize structural polymeric materials containing ester, ether and peptide linkages with multi-block, cyclic, star-shaped, (hyper-)branched, and cylindrical brush-like topologies. This research project aims to set up a novel methodology of Janus polymerization to extend the theory of ionic and coordination polymerization mechanisms.