Influence of CNT Concentrations on Structural and Morphological Properties of PANI-SnO2-CNT Nanocomposite Thin Films and the Sensitivity Performance to Detect E. coli in Water

Carbon nanotubes (CNTs) are particularly attractive for use in sensors for environmental and health monitoring. This study proposes a new approach in developing polymer-metal-based sensor for E. coli detection by using CNTs incorporation. PANI-SnO 2 nanocomposite thin films were combined with CNTs to be fabricated as biosensing devices. PANI-(SnO 2 ) 1-x -CNT x nanocomposite thin films were synthesized using sol-gel method and deposited on a glass substrate by spin coating technique. The prepared thin films were characterized by X-ray diffraction (XRD), field scanning electron microscopy (FESEM), atomic field microscopy (AFM) and ultraviolet-visible (UV-vis) spectroscopy. The sensitivity performance of PANI-(SnO 2 ) 1-x -CNT x nanocomposite thin films were conducted by using current-voltage ( I-V ) measurements. From the results, XRD patterns show the appearance of PANI, SnO 2 and C peaks and the increasing crystallite size with the increasing of CNT concentration. FESEM images show the spherical shape of SnO 2 and the nanotubes of carbon in the diameter size range 30 – 100 nm and 150 – 220 nm respectively. AFM analysis has found out the roughness parameter has increased when CNT percentage was increased. The peaks from UV-Vis absorbance bands indicated the presence of CNT and SnO 2 at wavelength 270 nm and 370 nm respectively. From I-V measurement of the sensor, PANI-(SnO 2 ) 1-x -CNT x with x = 0.03 performed the highest sensitivity which is 16.32%. The results demonstrate that the increasing of CNT concentrations was increasing the sensitivity of PANI-(SnO 2 ) 1-x -CNT x thin films towards E. coli .