Abstract：
Metal-free organic photocatalysts for photo-mediated reversible deactivation radical polymerization (photo-RDRP) are witnessed to make increasing advancement in the precise synthesis of polymers. However, challenges still exist in the development of high-efficiency and environmentally sustainable carbon dots (CDs)-based organocatalysts. Herein, N-doped CDs derived from phenanthroline derivative (Aphen) are prepared as metal-free photocatalysts for photoinduced electron transfer reversible addition-fragmentation chain transfer (PET-RAFT) polymerization. The introduction of phenanthroline structure enhances the excited state lifetime of CDs and expands the conjugated length of their internal structure to enable the light-absorption to reach green light region, thereby enhancing photocatalytic activity. The as-designed CDs exhibit unprecedented photocatalytic capacity in photopolymerization even in large-volume reaction (100 mL) with high monomer conversion and narrow polymer dispersity (Mw/Mn < 1.20) under green light. The photocatalytic system is compatible with PET-RAFT polymerization of numerous monomers and the production of high molecular weight polyacrylate (Mn >250 000) with exquisite spatiotemporal control. Above results confirm the potential of CDs as photocatalyst, which has not been achieved with other CDs catalysts used in photo-RDRP. In addition, the construction of fluorescent polymer nanoparticles using CDs as both photocatalyst and phosphor through photoinitiated polymerization-induced self-assembly (Photo-PISA) technology is successfully demonstrated for the first time.
摘要：
用于光介导的可逆失活自由基聚合（photo-RDRP）的无金属有机光催化剂在聚合物的精确合成方面取得了越来越多的进步。然而,在开发基于高效和环境可持续的碳点（CD）的有机催化剂方面仍然存在挑战。在这里，制备了源自菲咯啉衍生物（Aphen）的N掺杂CD，作为不含金属的光催化剂，用于光诱导电子转移可逆加成-断裂链转移（PET-RAFT）聚合。菲咯啉结构的引入提高了CD的激发态寿命，并扩大了其内部结构的共轭长度，使光吸收达到绿光区，从而提高光催化活性。设计的CD在光聚合中表现出前所未有的光催化能力，即使在大体积反应（100mL）中，在绿光下具有高单体转化率和窄聚合物分散性（Mw/Mn<1.20）。光催化体系与许多单体的PET-RAFT聚合和高分子量聚丙烯酸酯(Mn>250.000)的生产相容,具有精确的时空控制。以上结果证实了CD作为光催化剂的潜力，这在光RDRP中使用的其他CD催化剂中还没有实现。此外,首次成功证明了使用CD作为光催化剂和荧光粉通过光引发聚合诱导自组装（Photo-PISA）技术构建的荧光聚合物纳米颗粒。
