Dual-Functional Antenna Sensor for Highly Sensitive and Selective Detection of Isopropanol Gas Using Optimized Molecularly Imprinted Polymers

Abstract

Accurate monitoring of isopropanol (IPA) levels is crucial for safety in industrial and laboratory settings, as high concentrations can lead to serious health issues. In this study, we present, for the first time, a dual-functional antenna sensor capable of high-performance IPA gas detection with concentration estimation and uninterrupted wireless communication, using optimized molecularly imprinted polymer (MIP)/multiwalled carbon nanotube (MWCNT)-based sensing materials. Comprehensive characterization of these materials confirms the successful formation and homogeneity of the composites. Furthermore, the electrical and gas-sensing properties of the sensing materials were evaluated using functionalized interdigitated electrode (IDE)-based sensing structures, optimized for high sensitivity, were functionalized to evaluate the electrical and gas-sensing properties of the materials. These IDE structures, which acted as impedance-varying components during operation, were coupled with a single-port monopole antenna to develop a highly sensitive and selective gas sensor while maintaining uninterrupted communication services. The results showed that the fabricated sensor platform exhibits strong selectivity, sensitivity, and stability for IPA detection at room temperature, effectively distinguishing it from other interference gases. In addition, using the same sensing material, we demonstrated that the antenna-based gas sensor exhibited higher sensitivity than the chemiresistive sensor, achieving a detection limit (18.8 ppm) below the safety thresholds for IPA. Moreover, the antenna's radiation pattern and communication capabilities remained unaffected, ensuring uninterrupted functionality. Detailed optimization process and the sensing mechanism for a novel MIP-based selective antenna gas sensor, supported by both structural and electrical characterizations could serve as a milestone for future studies and the advancement of next-generation sensors.