Aligned Tubular Conjugated Microporous Polymer Films for the Aggregation-Induced Emission-Based Sensing of Explosives

This work shows the sensing performance of conjugated microporous polymer (CMP) tubes. Aligned tubular CMP films (CMP-AT) are synthesized by a template method. The Sonogashira coupling of tetra(4-ethynyl)phenylethylene with 1,4-diiodobenzene in the cylindrical pores of anodic aluminum oxide (AAO) plates and the etching of templates result in the CMP-AT films. Due to the tetraphenylethylene moieties in the materials, the CMP-AT films show aggregation-induced emission (AIE). Based on emission-quenching behavior, the sensing performance of CMP-AT films toward model explosives, nitrotoluenes, is studied. The CMP-AT films having longer CMP tubes with thinner wall thickness show better sensing performance with the Stern–Volmer constant (K_sv) values up to 92 400 M⁻¹ toward 2,4-dinitrotoluene. The reduced diffusion pathway of substrates by the thin wall of the CMP tubes is critical for the AIE quenching-based sensing of nitrotoluenes. These observations indicate that the functionality of CMP materials can be further enhanced by their morphological engineering. Due to the chemical stability of CMP materials, the CMP-AT-5 film can be recycled at least five times, maintaining the original sensing performance and tubular morphology.