Carbazole-functionalized nanocomposite fibers for sensitive alcohol vapor detection

The detection of alcohol vapors is essential for industrial safety, environmental monitoring, and public health, as excessive exposure can pose serious hazards. Recent advances in gas sensing technologies, such as metal oxide semiconductors, conducting polymers, and surface acoustic wave sensors, have shown promise for detecting volatile organic compounds (VOCs), but challenges such as slow response time, poor selectivity, and humidity interference remain unresolved. Optical sensing platforms, especially those based on nanofibers, offer a promising alternative for achieving real-time, label-free detection in ambient conditions. In this work, poly(methyl methacrylate) (PMMA) was selected as the sensing matrix due to its excellent optical transparency, mechanical flexibility, and compatibility with molecular dopants. Carbazole-based compounds are designed by grafting two 4,4′-dimethoxy-diphenylamine (DPA) and functionalize with alkyl chains of varying lengths: 1-bromocetane (C16), and was identified as the optimal structure (DPA-C16). Silver nanoparticles (Ag NPs) were incorporated to enhance sensing performance via surface plasmon resonance (SPR). DPA-C16 was electrospun with PMMA and Ag nanoparticles to form nanofiber-based optical sensing films for alcohol detection. This study highlights the role of carbazole-based DPA-C16 in enhancing the morphology and performance of electrospun nanofibers for alcohol gas sensing. DPA-C16 significantly improves hydrophobicity, effectively reducing moisture interference, and thereby enhancing sensor stability in humid conditions. Optimized electrospun fiber materials exhibit rapid response times of less than one minute and high sensitivity with a detection limit of 50 ppm for methanol, ethanol, and isopropanol. The developed material demonstrates efficient and highly selective gas sensing capabilities, making it a strong candidate for industrial detection, environmental monitoring, and safety applications.