环境友好的可控自由基聚合

近年来，我们以环境友好、简便快捷、活泼可控、单体普适性强的光活化室温RAFT聚合为主攻目标，针对长波紫外或可见光活化室温RAFT聚合反应特征及其应用展开了深入探讨。研究表明，作为RAFT聚合链转移剂的硫酯化合物具有分别在紫外光和可见光波段的双波段光吸收特征。短波紫外光强吸收，导致硫酯键的光解。然而，可见光波段弱的光吸收则活化其自由基加成产物的断裂反应，加速室温RAFT过程并确保聚合反应的活性特征。高效光引发，可显著缩短RAFT聚合引发期。通过光开关，可实时启动或终止聚合。与常规热聚合不同，室温以下这类聚合反应不存在明显的热活化效应。由此，我们创建了环境友好、单体普适性强、快速可控、通过光开关可实时控制聚合反应启动或终止的光活化室温RAFT聚合，将其成功拓展到太阳光和水溶液聚合体系，并运用于温和条件下新兴水溶性温敏高分子、仿生光响应高分子的快捷可控合成。

Environmentally Friendly and Controlled Radical Polymerization

In recent years, our work focused on the development of light-activating ambient temperature RAFT polymerization to be environmentally friendly, facile and rapid, living and well-controlled, and suitable for a variety of monomers. Our results demonstrate that as chain transfer agents(CTA) of RAFT polymerization, the thiocarbonylthio compounds exhibit absorptions separately in UV and visible light ranges. The strong UV absorption leads to the photolysis of CTA functionalities, but the weak absorption in visible light wave range may significantly activate the fragmentation reaction of their intermediate radicals, thus accelerate the RAFT process without loss of its living character. High efficiency of photo-initiation may significantly shorten the initialization period. Thermo-activation of this polymerization is negligible below 30oC. This polymerization immediately starts or ceases upon switching on or off this visible light. Accordingly, we exploited a facile, rapid and well-controlled visible light activating ambient temperature RAFT polymerization. This environmently friendly approach may extend to the solar light activation or in aqueous solution, and for the synthesis of thermo-responsive water-soluble polymers and biomimetic photo-responsive polymers.Contents 
1 Introduction 
2 Our opportunity: UV-vis spectra characters of chain transfer agents for RAFT polymerization 
3 Ambient temperature RAFT polymerization under long-wave UV radiation 
4 Ambient temperature RAFT polymerization under visible light radiation
5 Ambient temperature RAFT polymerization under solar light radiation
6 Ambient temperature RAFT polymerization in aqueous solution under long-wave UV radiation 
7 Applications of ambient temperature RAFT polymerization under visible light radiation 
7.1 Rapid and well-controlled synthesis of novel thermo-responsive water-soluble polymers 
7.2 Rapid and well-controlled synthesis of biomimetic photo-responsive functional polymers 
8 Conclusions and outlook