Wearable HKUST-1 MOF Sensor on N95 Fabric for Electrochemical Detection of Simulant for Nerve Agent DMMP

This study reports the development of an innovative, wearable chemical sensing platform based on nanostructured HKUST-1 metal–organic frameworks integrated onto N95 facemask fabrics, functionalized with the ionic liquid (IL) 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMIM+ OTf–) for the detection of dimethyl methylphosphonate (DMMP), a widely recognized sarin nerve-agent simulant. Structural and compositional analyses conducted through vibrational and electron beam-based characterization confirmed successful nanoporous integration of HKUST-1 and IL onto the N95 substrate, demonstrating stable coordination between Cu metal centers, IL, and DMMP. Electrochemical impedance spectroscopy highlighted the sensor’s remarkable conductivity enhancement upon DMMP exposure, showing a conductivity increase from 2.10 × 10–4 S cm–1 (blank sensor) to 27.5 × 10–4 S cm–1 (32 × 10–6 mol mm–2 DMMP), attributed to facilitated ion mobility and interfacial charge transport across the micronano junctions of the IL–MOF composite. A calculated detection limit of 13 × 10–7 mol mm–2 DMMP emphasizes the sensor’s high sensitivity and potential for real-time, molecular-scale detection. Furthermore, humidity-dependent EIS studies underscored synergistic effects between moisture, DMMP, and IL-MOF composite, significantly boosting conductivity even at lower humidity levels. This advanced MOF-IL functional textile demonstrates strong potential as a flexible, solid-support sensing substrate for rapid and sensitive liquid-phase chemical detection.