The Study on the Application and Characterization of Conductive Polyaniline

• Main Authors: Shih-Pong Lee, 李世鵬
• Other Authors: Yaw-Shun Hong ,Chi-Man Ho,Chang-Ping Chang
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/54462903416384232411

博士 === 國防大學中正理工學院 === 國防科學研究所 === 96 === A prototypical conjugated polymer, polyaniline(PAn),was examined for chemosensor application to detect chemical warfare agents (such as incapacitating agents and tearing agents simulants) and 3,4-Dinitrotoluene(3,4-DNT), Trinitrotoluene(TNT) and Picric acid(PA) explosives. The equilibrium adsorption of chemical agents and explosives were analyzed under polyaniline sensor condition by 4-point probe resistivity sheet resistance tester and semiconductor parameter analyzer, sensitive to changes in surface resistance and conductivity. The results of the experiments show that responses to the chemical agent simulants and the explosives can be achieved with higher semiconductivity samples. In summary, conductivity-based chemosensing method merits attention because of its sensitivity, selectivity and simplicity. The fact that polyaniline showed high conductive sensitivity toward incapacitating agent simulants indicated it is potential candidates chemosensor material for detecting chemical warfare agents and the explosives. Microwave absorbents with core-shell structure of Mn1-xZnxFe2O4-Polyaniline have been synthesized by the polymerization of aniline in the aqueous solution of aniline in the presence of surfactant NaDS and the nano-particle size powder of Mn1-xZnxFe2O4. The nano-partical size of Mn1-xZnxFe2O4 were prepared with the method of self-propagation combustion of the aqueous sol-gel. X-ray powder diffiration of ferrites indicated that the structure of core materials are spinel structures with lattice constants around 8.44Å to 8.40 Å. SEM and TEM photographs show that the particle size of core material are around 100nm to 200nm. After coating with polyaniline, the particle size of the core-shell of ferrite-polyaniline have grown up to 400nm~800nm. The conductivity of the core materials ferrites and of the core-shell materials of the ferrite-polyaniline measured by the four point probe resistivity are 10-5Ω-1．cm-1 and 10-1Ω-1．cm-1 respectively. The conductivity of the core-shell materials increase with the increasing of the amount of polyaniline in the resulting products. The magnetic hysteresis loops of materials intvestigated with VSM indicate that the saturated magnetization(Ms) of pure spinel ferrites of Mn1-xZnxFe2O4 increase with the x value up to 47.01em/g for Mn0.50Zn0.50Fe2O4, but the Ms values of the core-shell materials decrease with the amount of polyaniline(PAn) in the core-shell ferrite-polyaniline materials. The composite specimens of the core-shell ferrite-polyaniline and epoxide resine has band-with microwave absorption of the reflection lose -5dB to -10dB at the frequency between 4.5 GHz and 6.8 GHz were also observed by the network analyzer. A nanoparticle of Ba(ZnTi) Fe10O19-PAn with core-shell structure exhibiting electrical and ferromagnetic properties can be synthesized by in situ emulsion polymerization. The conductivity of the composites depended on PAn content. The magnetic properties of the resulting composites showed ferromagnetic behavior, such as saturated magnetization and coercive force. The saturated magnetization and coercive force increased with the increasing Ba(ZnTi) Fe10O19 content. A structural characterization by SEM and powder X-ray diffraction, proved that nanometer-size of Ba(ZnTi) Fe10O19-PAn with core-shell structure were about 200-500nm. The results of TGA and the four point probe resistivity indicated that Ba(ZnTi) Fe10O19 nanoparticles could improve the composite thermal stsbility and could decrease the conductivity.