Novel TPU/Fe2O3 and TPU/Fe2O3/PPy nanocomposites synthesized using electrospun nanofibers investigated for analyte sensing applications at room temperature

In this work, non-conducting electrospun thermoplastic polyurethane (TPU) nanofibers have been successfully embellished with the filler materials viz. ferric oxide (Fe2O3) and polypyrrole (PPy) to synthesize the conducting TPU/Fe2O3 and TPU/Fe2O3/PPy nanocomposites. The electrical, morphological, elemental analysis and structural characteristics of the nanocomposites are examined through I-V characterization, energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. To confirm the composite formation Fourier transform infrared spectroscopy (FTIR) results are used. As evolved nanocomposites are employed for developing the ultra-responsive and highly stable analyte sensors. The analytes sensing characteristics of both the sensors have been successfully carried out in concentration range 100 ppb to 500 ppm at room temperature (RT) under 45 % relative humidity (RH) conditions. TPU/Fe2O3 sensor is found to be significantly sensitive towards the ethanol detection with appreciable % response (similar to 21 %) for low ethanol concentration (100 ppb i.e. 0.1 ppm) with rapid response (8 s) and recovery (10 s) times. In addition, TPU/Fe2O3/PPy sensor is found highly suitable for ammonia sensing applications, having sufficiently high % response viz. similar to 69 % for 100 ppb and similar to 900 % for 500 ppm of ammonia concentrations with appreciable response and recovery times. The stability of both the sensors have been monitored by continuously measuring the response for 10 weeks. The effect of humidity on the sensing characteristics of both the sensors is also analysed under humidity range 45 %RH to 85 %RH.