Durable and recyclable conjugated microporous polymer mediated controlled radical polymerization under white LED light irradiation

Photo-induced controlled radical polymerization (CRP) using heterogeneous catalysts offers excellent spatiotemporal control and has attracted special attention owing to its potential for green chemistry and biomedical applications. Herein, an imine-based conjugated microporous polymer material (EI-CMP) with high stability, recyclability and catalytic efficiency was synthesized under mild conditions. An alkyl radical (R˙) from alkyl iodide (R-I) with EI-CMP under white LED light was generated to initiate polymerization. Polymers with narrow molecular weight dispersity and controllable molecular weight can be produced by the polymerization of some functional methacrylates. Without photoirradiation, no polymerization occurs, suggesting that the polymerization is an ideal photo “on”–“off” switchable system. The high chain-end fidelity of iodine end-capped poly(methyl methacrylate) was confirmed by a chain-extension reaction. The catalytic ability of EI-CMP did not decrease after three cycles. An attractive feature of this method is the development of a heterogeneous photocatalyst which enables easy separation and efficient reusability.