A series of N-alkyl-substituted polybenzimidazoles (SPBIs), synthesized by simple condensation and N-alkylation, act as functional materials with tunable microstructures and sensing performance. For their controllable morphologies, the formation of nano-/microspheres is observed at the n(RBr)/n(PBI) feed ratio of 5:1. Products with different degrees of alkylation can recognize metal ions and nitroaromatic compounds (NACs). For example, SPBI-c, obtained at the feed ratio of 1:1, can selectively detect Cu²⁺, Fe³⁺, and NACs. By contrast, SPBI-a, obtained at the feed ratio of 0.1:1, can exclusively detect Cu²⁺ with high sensitivity. Their sensing mechanisms have been studied by FT-IR spectroscopy, SEM, XPS, and DFT calculations. Interestingly, the SPBIs can adsorb Cu²⁺ in solution and show good recyclability. These results demonstrate that polymeric materials with both sensing and adsorption applications can be realized by regulating the alkylation extent of the main chain, thus providing a new approach for the facile synthesis of multifunctional materials.

通过简单的缩合和N-烷基化合成的一系列N-烷基取代的聚苯并咪唑 ( SPBI )作为具有可调微结构和传感性能的功能材料。对于它们的可控形态，在n (RBr)/ n (PBI) 进料比为 5:1 时观察到纳米球/微球的形成。具有不同烷基化程度的产品可以识别金属离子和硝基芳香化合物 (NAC)。例如，进料比为 1:1 时获得的SPBI-c可以选择性地检测 Cu ²⁺、Fe ³⁺和 NACs。相比之下，进料比为 0.1:1 时获得的SPBI-a可以专门检测 Cu²⁺具有高灵敏度。它们的传感机制已通过 FT-IR 光谱、SEM、XPS 和 DFT 计算进行了研究。有趣的是，SPBI可以吸附溶液中的Cu ²⁺并显示出良好的可回收性。这些结果表明，通过调节主链的烷基化程度可以实现兼具传感和吸附应用的聚合物材料，从而为多功能材料的简便合成提供了新的途径。