Sensing Properties And Mechanisms Of Conducting Polymers Polyaniline And Polyp Yrrole

With the accelerating development of industry modernization, the pollution caused by industrial raw materials, especially harmful gas, has brought much trouble to industrial production. In order to monitor harmful gas, the development and research of gas sensor become more and more important. However, the traditional gas sensitive materials mainly consist of metal oxides, and sensors based on that are generally operated at high temperature, therefore, conducting polymer sensors arise at the historic moment. This paper studys the preparation and modification of conducting polymer polyaniline and polypyrrole, as well as the discussion on mechanism of enhanced gas sensitivity.We prepared a heterostructure hybrid of PANI and SnO2 by a rapid and facile in situ chemical oxidation polymerization under very low monomer concentration, and the hybrid was loaded on a flexible PET thin film to structure a smart NH3 sensor. The structure and morphology of the hybrid were characterized by various analysis methods. The hybrid based sensor not only has high sensitivity, good selectivity and wide linear response to NH3 at room temperature but also has flexible, structure simple and portable performance. The improvement of sensing properties is attributed to the complementary and synergistic effect between SnO2 and PANI, and formation of p-n heterojunction at the interface in hybrid.Polypyrrole nanoparticles loaded on a flexible polyethylene terephthalate film were fabricated by in situ chemical polymerizations using FeCl3 as oxidant in the presence of various surfactants. The structure and morphology of PPy prepared have been characterized by various analysis methods, such as scanning electron micrographs, X-ray powder diffraction, Fourier transform infrared and four probe methods. The sensor based on PPy nanoparticles synthesised using sodium dodecyl sulfate as surfactant exhibits high sensing response to ppm level triethylamine at room temperature. The result clearly indicates that the surfactants play a decisive role in the polymerization rate and the morphology of the polymer, thus strongly affect the gas sensing properties to TEA.