Controlled microflow cationic polymerization of vinyl ethers under ambient conditions

• First microflow cationic polymerization under ambient conditions. • No further purification of all reagents were required. • Well-defined poly(vinyl ether)s can be achieved within 2 min. Living cationic polymerization is a well-established method for preparing polymers with controlled molecular weights and complex architectures, but rigorous polymerization conditions limit its widespread application. Here, we report a facile strategy for simplifying the strict conditions required for traditional living cationic polymerizations of various vinyl ethers including ethyl vinyl ether (EVE), propyl vinyl ether (PVE), butyl vinyl ether (BVE) and isobutyl vinyl ether (IBVE) by utilizing continuous microflow reactors and a weak Lewis acid, zinc chloride (ZnCl 2 ). Well-defined polymers with controlled molecular weights and narrow molecular weight distributions (<1.20) can be obtained under ambient conditions without monomer purification, temperature control or strictly anhydrous conditions. The living nature of the polymerization was verified by kinetic experiments and successful in situ chain extension.