Electrospun nanocomposite fiber mats as gas sensors

Electrospinning was used to spin nanocomposite fiber mats from polymer solutions containing nanoparticles. The base polymer was polyacrylonitrile (PAN), and the nanoparticles included iron oxide, antimony tin oxide and zinc oxide with diameters ranging from 10 to 70 nm. The electrospun nanocomposite fiber mats were characterized by scanning electron microscopy (SEM), scanning probe microscopy (SPM) and Fourier transform infrared (FTIR) spectroscopy. The average fiber diameter was found to decrease from 200 nm for neat PAN fibers to 50–150 nm for nanocomposite fibers. The porosity increased from 70% for PAN fiber mat to an average of 86% for nanocomposite fiber mats. The fiber mats were used as a sensor in conjunction with FTIR spectroscopy to detect CO2 gas. The absorbance spectra showed a higher sensitivity with a fiber mat, regardless of its type, than without, indicating gas adsorption on the fiber mat. The highest sensitivity was obtained with PAN/Fe2O3 fiber mat. As the underlying mechanism is physisorption rather than chemisorption, the response time was short and the sensor could be used repeatedly.