MWCNT-polymer composites as highly sensitive and selective room temperature gas sensors

摘要

Multi-walled carbon nanotubes (MWCNTs)-polymer composite-based hybrid sensors were fabricated and integrated into a resistive sensor design for gas sensing applications. Thin films of MWCNTs were grown onto Si/SiO_2 substrates via xylene pyrolysis using the chemical vapor deposition technique. Polymers like PEDOT:PSS and polyaniline (PANI) mixed with various solvents like DMSO, DMF, 2-propanol and ethylene glycol were used to synthesize the composite films. These sensors exhibited excellent response and selectivity at room temperature when exposed to low concentrations (100ppm) of analyte gases like NH_3 and NO_2. The effect of various solvents on the sensor response imparting selectivity to CNT-polymer nanocomposites was investigated extensively. Sensitivities as high as 28% were observed for an MWCNT-PEDOT:PSS composite sensor when exposed to 100ppm of NH3 and - 29.8% sensitivity for an MWCNT-PANI composite sensor to 100ppm of NO_2 when DMSO was used as a solvent. Additionally, the sensors exhibited good reversibility.