Photoinduced electron/energy transfer-reversible addition–fragmentation chain transfer (PET-RAFT) polymerization has emerged as a versatile and highly-efficient method for the polymerization of more activated monomers including N,N-dimethylacrylamide and methyl acrylate, and less activated monomers including N-vinylpyrrolidone and vinyl acetate, whilst imposing composition, sequence and spatiotemporal regulation. Although significant progress has been achieved in terms of ability to regulate PET-RAFT polymerization through the implementation of myriad environmental cues, it is still a great challenge to introduce multiple external switches within a single catalyst to accomplish logic toggling of controlled radical polymerization (CRP). Herein, we report the synthesis and characterization of Fe₃O₄@aSiO₂@PNMIr Janus nanocomposites coupled with immobilized heteroleptic iridium(III) complexes for heterogeneous catalysis of PET-RAFT polymerization. With this catalytic nanoarchitecture, we demonstrate multi-stimuli switching of CRPs using three different external physical manipulations: light “ON”/“OFF”, magnet “OUT”/“IN” and temperature “LOW”/“HIGH”. In addition, these magnetic Janus nanocomposites endowed radical polymerization with various attractive characteristics such as compatibility of myriad monomer formulations including “more activated” and “less activated” monomers, unique oxygen tolerance and ppm-level catalyst dosage. Logic-controlled polymerization with Fe₃O₄@aSiO₂@PNMIr nanocomposites provides a straightforward, robust and user-friendly strategy for realizing multiplexed external switching of polymer propagation using a single nanocatalyst without the involvement of exogenous reagents.

中文翻译：

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具有铱（III）配合物的磁性Janus纳米复合材料，用于使用多路外部开关进行逻辑控制的RAFT聚合的多相催化

光诱导的电子/能量转移可逆加成-断裂链转移（PET-RAFT）聚合已经成为一种通用且高效的方法，用于聚合更多活化的单体，包括N，N-二甲基丙烯酰胺和丙烯酸甲酯，而活化较少的单体包括ñ-乙烯基吡咯烷酮和乙酸乙烯酯，同时强加了组成，序列和时空调节。尽管通过实施多种环境线索在调节PET-RAFT聚合能力方面已取得重大进展，但在单个催化剂中引入多个外部开关以实现受控自由基聚合（CRP）的逻辑切换仍然是一个巨大的挑战。 。此，我们报告Fe的合成和表征₃ ö ₄ @一个的SiO ₂ @PNMIr詹纳斯纳米复合材料加上固定杂合铱（III）用于PET-RAFT聚合非均相催化的配合物。通过这种催化纳米结构，我们展示了使用三种不同的外部物理操作对CRP进行多刺激切换：“ ON” /“ OFF”光，“ OUT” /“ IN”磁体和“ LOW” /“ HIGH”温度。此外，这些磁性Janus纳米复合材料赋予自由基聚合以多种吸引人的特性，例如多种单体配方（包括“更多活化”和“更少活化”单体）的相容性，独特的耐氧性和ppm级催化剂用量。Fe ₃ O ₄ @ a SiO _2的逻辑控制聚合@PNMIr纳米复合材料提供了一种直接，可靠且用户友好的策略，可使用单个纳米催化剂实现聚合物传播的多重外部转换，而无需使用外源试剂。