聚苯胺复合薄膜气体传感器的制备及特性研究

【作者】 陈璇；

【导师】 蒋亚东；

【作者基本信息】 电子科技大学 ， 电子信息材料与元器件， 2008， 硕士

【摘要】 气体传感器是一类重要的化学传感器，在航空航天、石油化工、环境及食品等领域有着广泛的应用。气敏材料是气体传感器的核心，与传统的TiO₂、SnO₂、ZnO等无机半导体材料相比，高分子气敏材料聚吡咯、聚噻吩、聚苯胺等具有价廉易得、制备简单的优点，最重要的是它可以在室温下使用，从而拓展了气体传感器的应用范围。而相对于其他共扼高分子体系，聚苯胺由于独特的掺杂机制、良好的导电性、优良的环境稳定性等优点而成为最具有应用前景的导电高分子材料之一。然而单一的聚苯胺分子间相互作用力大，几乎不溶不熔，加工性能和机械性能差，使得很多实际应用无法实现。而聚苯胺与纳米粒子复合的复合材料既能发挥纳米粒子自身的小尺寸效应、表面效应和量子效应而且兼有高分子材料本身的优点使得它们在光、电、磁、敏感等方面呈现出常规材料不具备的特性，故而得到广泛的研究。针对以上问题，本文主要研究了以几个部分：（1）采用静电力自组装和化学氧化聚合相结合的方法，以苯胺为单体，过硫酸铵为氧化剂，在酸性介质中分别制备了PANI／TiO₂复合薄膜和PANI薄膜，对其进行了表征分析和气敏特性的研究。结果表明，PANI／TiO₂复合薄膜传感器在对NH₃灵敏度、响应-恢复时间和重复性等方面均优于PANI薄膜传感器。接着研究了质子酸掺杂剂对PANI/TiO₂氨敏特性的影响。分别用HCl和PTSA作为质子酸掺杂剂，制备了HCl和PTSA掺杂的PANI／TiO₂复合薄膜，分别对其进行了表征分析和氨敏特性的研究。结果表明，HCl掺杂比PTSA掺杂复合薄膜传感器有更高的灵敏度和更短的响应-恢复时间，而两者的重复性均较为理想，但稳定性很差，因而在此基础上，又研究了聚合温度对PANI/TiO₂复合薄膜传感器氨敏特性的影响，结果表明10℃下制备的复合薄膜传感器的灵敏度最高，响应-恢复时间最短。（2）选用另外一种常见的无机半导体SnO₂纳米颗粒作为掺杂剂，相同的实验条件下分别制备了不加入表面活性剂TTAB和加入TTAB的PANI／SnO₂复合薄膜传感器，通过对薄膜表征分析和气敏特性的研究可知，表面活性剂TTAB的加入大大提高了高浓度NH₃的灵敏度，在响应-恢复时间上也得到了一定的改善。更多还原

【Abstract】 Gas sensor is a kind of important chemical sensors, which is widely used in many fields such as aviation and spaceflight, petrolic and chemical industry, environment and foodstuff inspection. Gas-sensing materials are the center of gas sensor. Comparing with the conventional gas-sensing materials（TiO₂、SnO₂、ZnO and so on）, macromolecular gas-sensing materials（polypyrrole, polythiophne, polyaniline and so on）expand the application range of gas sensors, due to their low cost, simple preparation and being used at room temperature. In comparision with other conjugate polymers, PANI is cheaper, which is easily polymerized, with high conductivity and a broad prospect for application. However, because of the rigid nature of its chain backbone, PANI is difficult to dissolve and melt. It is difficult to be put into practical application. The PANI composites are widely used in a lot of fields such as optic field, electronical field, magnetic field, sensitive field and so on, because it not only has small size effect, surface effect and quantum effect of the nano-particles, but also has advantage of macromoclecule. Aiming at solving the problem mentioned above, the thesis contained two sections as follows:First, PANI and PANI/TiO₂ thin films were prepared by in-situ chemical oxidation polymerization and electrostatic self-assembly combined technique. The films were characterized by scanning electron microcopy （SEM）, UV-Vis absorption spectrum and FTIR. At the same time, the sensitivity of the PANI and PANI/TiO₂ film sensors to toxic gase NH₃ were tested. The results showed that the PANI/TiO₂ film sensor had a better charateristic than PANI film sensor in sensitivity and its response-recovery time was shorter than PANI film sensor. Then the effect of proton acid dopants on the PANI/TiO₂ composite thin films was studied. PANI/TiO_<sub>2 composite thin film doped by HCl and PTSA were prepared in the same method. SEM, UV-Vis absorption spectrum and the sensitive properties of sensors to NH₃ were studied. The results showed that the sensitivity, response and recovery characteristic of PANI/TiO₂ composite thin film doped by HCl were superior to that of PANI/TiO₂ composite thin film doped by PTSA, whereas both of the sensors were bad in stability. And the effect of various polymerization temperatures on the sensors was studied. As a result, it showed that the sensor made under 10℃had the best sensitivity and the shortest response and recovery time.Second, SnO₂ was chosen as the dopant. PANI/SnO₂ and PANI/SnO₂-TTAB gas sensors were made in the same method. SEM, UV-Vis absorption spectrum and FTIR were used to characterize the composite films. Through the analysis of the sensitivity to NH₃ and the response and recovery time, PANI/SnO₂-TTAB gas sensor had the higher sensitivity, and its response and recovery time improves a lot.更多还原