I-D Kim, A. Rothschild, H.L. Tuller, D.Y. Kim and S.M. Jo
nanofibers, electrospinning, gas sensors, CWA detection
TiO2 fiber mats were deposited onto Al2O3 substrates with interdigitated Pt electrodes by means of electrospinning from a solution of DMF and PVAc synthesized using bulk radical polymerization of titanium propoxide and acetic acid as a catalyst. Subsequently, the samples were calcined to remove the organic constituents and crystallize the fibers into the anatase phase. The resultant fibers had a bundle structure consisting of ~20 nm thick fibrils. This unique morphology results in an exceptionally high surface-to-volume ratio, highly advantageous for gas sensors. The specific surface area measured by BET was 90 m2/g. <br>These sensor prototypes demonstrated exceptional sensitivity to NO2, with response magnitudes as high as ~100 upon exposure to some tens of ppm of NO2, identifying them as promising candidates for gas sensors in environmental and medical applications in which sub-ppm levels of NO2 need be detected. The response to reducing gases, while not as high as for NO2, was still significant. Amongst the gases tested in this study, the sensitivities to H2 and DMMP where significantly higher than for CO and CH4. In particular, the response to DMMP indicates an ability to detect small traces of DMMP vapors, making them candidates for CWA detectors in security applications.