| Description |
Explosives and drugs cause problems in society when used inappropriately. It is highly desired to detect these chemicals in a quick and reliable way with low cost. Vapor detection of explosives and drugs has been proven to be one of the most effective, practical, and noninvasive methods. Among all the methods developed so far, highly sensitive carbon nanotube-based (CNT-based) chemiresistive sensors remain promising. In this dissertation, we explored and developed three CNT-based sensors for the explosive and drug detection. In this dissertation, we proposed that the dominant mechanism of our oligomer-coated CNT-based sensors is due to the swelling of the oligomers. Based on this swelling mechanism, we have designed three oligomers or polymers functionalized CNT-based sensors for the detection of nitro-explosives, alkanes (related with ammonium nitrate/fuel oil), and amines (related with methamphetamine), respectively. Beyond the high sensitivity to the target analytes, the selectivity of the sensors was largely enhanced by the careful selection of oligomers and polymers. The three oligomers and polymers under investigation can enhance the interaction between the sensor and the analyte, and facilitate the dispersion of CNTs in a solution. For the detection of nitro-explosives, we chose an oligomer that had been successfully demonstrated as a fluorescence-based nitro-explosive sensing materials. For the detection of alkanes and amines, we introduced the alkane side chains and carboxylic acid functional groups in the polymer. This dissertation demonstrated three examples of oligomer or polymer functionalization CNT-based sensors for the detection of explosives and drugs. Meanwhile, the dominant mechanism of the sensors was proposed. This research paved ways for developing chemical vapor sensors with better sensitivity and selectivity in the future. |
