Preparation of flexible VOC sensor based on carbon nanotubes and gold nanoparticles

Novel flexible volatile organic compound (VOC) sensor was prepared by deposition of gold nanoparticle (AuNP) and amine modified multi-walled carbon nanotubes (MWCNT-NH2) on polyimide substrate via electrospraying technique. First, interdigitated electrodes (IDE) were fabricated on polyimide (Kapton®) substrate by photolithography. Then, the substrates were subjected to oxygen plasma etching, followed by electrospraying of AuNP and MWCNT-NH2 solution on the substrate. The thin films were characterized by FE-SEM and AFM as well as electrical conductivity measurement. Chemical sensing behaviors of the sensors were analyzed against polar (water, propanol and ethanol) and nonpolar (hexane, toluene, trichloroethylene and chloroform) VOCs. In addition, effect of the AuNP/MWCNT-NH2 ratio on the conductivity and sensing was investigated. Bending test (100 times) resulted in negligible resistance change, demonstrating the successful preparation of flexible sensor.