Preparation Of Ultra-fine Polyaniline Tubes By A Template Method And Gas Sensitivity Studies

In the paper, A facile route has been demonstrated for the synthesis of ultra-fine conducting polyaniline (PANI) tubes. The structure of the conducting PANI tubes synthesized by using electrospun nitrocellulose (NC) as a suitable fiber template, since it can be processed into fibers with diameters in the sub-micrometer range by a electrospinning and has very good solubility in acetone solution. the ultra-fine PANI tubes was obtained by dissolving templates. Meanwhile, The value of gas-sensitivity to NH3 was also examined at room temperature . The main results are obtained as follow:1. PANI tubular doped with H4SiW12O40 is synthesized by using electrospun nitrocellulose (NC) as a suitable fiber template polymerization of aniline . The structure of the conducting PANI tubes synthesized by dissolving the template is characterized by IR spectrum and wide-angle X-ray diffraction (XRD). Scanning Electron Microscopy (SEM) and transmission electron microscopy (TEM) investigate the morphology and average diameter of the ultra-fine PANI tubes. Thickness of tubes wall increased with increased the ratio of aniline/ ammonium. The conductivity of the doped PANI tubes is 7.8×10-2 Scm-1.2. HPA-PANI tubular were adhered on a porcelainize substrate having a pair of interdigitated Pt electrodes. The gas-response to NH3 was also examined at room temperature. It was found that the value of gas-sensitivity increased with thickness of tubes wall decreased. As shown that the thickest of PANI tubes wall have excellent gas sensing performance to very low concentration NH3 gas.3. PANI fibers doped with inorganic acids (HCl H2SO4 H3PO4) is prepared through a chemical oxidation method by using electrospun nitrocellulose (NC) as a suitable fiber template. The structure of the conducting PANI tubes synthesized by dissolving the template is characterized by IR spectrum and wide-angle X-ray diffraction (XRD). Scanning Electron Microscopy (SEM) and transmission electron microscopy (TEM) investigate the morphology. The results indicate that the surface of the PANI-H3PO4 shows the shape is smooth and shapely.4. The gas sensitivity to a series of chemical vapors is examined at the room temperature. The results indicate that the ultra-fine PANI tubes have significantly better performance in both sensitivity and rapid response to ammonia than trimethyl-amine and hydrazine. The gas-response to NH3 was also with regular the ultra-fine PANI-H3PO4 tubes structure is much better than those of irregular PANI-HCl PANI-H2SO4 tubular.