Carbon Nanotube-Based Molecularly Imprinted Polymer Antenna Sensor for Ambient Methanol Vapor Detection

This study introduces a novel antenna sensor that incorporates molecularly imprinted polymers (MIPs) to selectively detect methanol vapor under room temperature conditions, thereby eliminating the requirement for preheating the analyte. The selection of methanol as the target analyte was based on its dual significance, serving as both a prevalent industrial hazard and a relatively nontoxic model for volatile pollutants. A conductive polymer composite consisting of MIPs modified with carbon nanotubes (CNTs), with a high affinity for methanol, was drop-cast onto a resonant patch antenna operating at a frequency of 3.490 GHz. The resulting copper-layered antenna, integrated with the MIP-CNT composite, demonstrated exceptional sensitivity and selectivity for methanol vapor detection under ambient conditions. Real-time sensing was enabled to continuously monitor the antenna’s reflection coefficient (S11) within a controlled chamber exposed to methanol vapor. Notably, our MIP-CNT composite exhibited selectivity by discriminating against common interferents, including other alcohols. We achieved a limit of detection of 0.5 mmol dm−3, with consistent and reliable responses up to 6 mmol dm−3. This research underscores the significant potential of MIPs in antenna-based gas sensors and contributes to the advancement of selective and sensitive pollutant monitoring technologies.