Dual-phase formaldehyde detection via catalyst-triggered AIE in metal-coordinated supramolecular polymers

It is essential to develop a simple method for detecting formaldehyde (FA) because of its harmful effects on human health. Herein, we present a novel metal-coordinated supramolecular polymer chemosensor utilizing a complex between the tetraphenylethylene (TPE) derivative (T4J) and Cu²⁺ for FA detection in both gaseous and aqueous phases. In this system, Cu(NO₃)₂ acts as both a linker and a promoter, enabling selective FA detection by T4J-Cu through an aggregation-induced emission (AIE) mechanism. This configuration affords a clear fluorescence turn-on response that can be recognized by the naked eye with a calculated limit of detection (LOD) of 17.5 nM. A practical FA detection kit was fabricated by immobilizing T4J-Cu onto test paper substrates, allowing field-deployable analysis of FA-contaminated environments with preserved sensitivity. Meanwhile, at the same concentration, T4J-Cu exhibited high adsorption efficiencies for 1 × 10^-2 and 1 × 10^-3 M FA, achieving 85% and 88%, respectively, making it a candidate adsorbent for FA. The proposed metal-coordinated supramolecular polymer strategy, coupled with Cu²⁺-accelerated hydrazone formation and the reaction-triggered AIE luminescence enhancement, establishes a novel paradigm for FA sensing. This methodology exhibits significant potential for expansion to diverse volatile organic compound (VOC) monitoring applications, particularly in scenarios requiring rapid on-site detection capabilities.