ZnO和导电高分子纳米复合气敏材料的制备及其敏感特性研究

发布时间：2018-05-07 18:31

本文选题：ZnO + PPy　；参考：《浙江大学》2017年硕士论文

【摘要】：气体传感器在农业、军事、环境等领域有着广泛的应用,随着信息社会的快速发展,对传感器的性能提出了更高的要求。采用纳米材料或复合材料等方法可以显著改善传感器的响应特性,已经成为该领域的研究热点。本论文提出一种静电纺丝结合水热合成方法,在基底上原位制备了纳米结构ZnO。通过水热条件的改变调控其形貌结构,得到了 ZnO纳米粒子和纳米片。反应在水体系中进行,无需加入有机溶剂和其它添加剂;同时避免了高温灼烧和对纳米材料的二次分散,过程简便易行,具有绿色环保的优点。采用气相聚合方法在ZnO表面沉积聚吡咯(PPy),制备了 PPy/ZnO 纳米复合材料;利用 FESEM、XRD、FT-IR、HRTEM等手段对复合材料的形貌、组成和结构进行了表征。考察了复合物对于NH3的室温响应特性,研究了 ZnO形貌对复合物响应特性的影响。结果显示:ZnO纳米片和PPy的复合物具有最佳的响应特性,其对于10 ppm NH3的电阻相对变化为76%,比PPy的响应灵敏度提高了近30倍,同时体现出优异的选择性和良好的重复性。对复合物响应机理的研究表明,复合物与基底的良好接触,纳米结构带来的高比表面积以及PPy和纳米ZnO界面形成的p-n结均有助于复合物响应灵敏度的提升,其中p-n结的形成具有关键性作用。采用后掺杂法、快混法以及聚合物酸模板法等制备了具有不同形貌结构的可分散导电态聚苯胺(PANI)。将PANI浸涂于不同纳米结构的ZnO表面,或者通过溶液及气相聚合方法在纳米结构ZnO表面沉积PANI,制备PANI/ZnO纳米复合物,表征了其组成和形貌结构。考察了 PANI/ZnO纳米复合物对于NH3的室温响应特性,研究了 ZnO的纳米结构、PANI的形貌结构以及制备方法等对复合物敏感特性的影响。发现气相聚合PANI和ZnO纳米片复合物的响应灵敏度最高,对10 ppm NH3的电阻相对变化高达2150%,较PANI提高了 10倍。同时,复合物具有超低的检测限(5ppb),优异的选择性和良好的重复性。探讨了复合物的气敏响应机理,认为纳米结构以及ZnO和PANI之间形成的p-n结结构的存在显著提高了复合物的响应灵敏度。
[Abstract]:Gas sensors are widely used in agriculture, military, environment and so on. With the rapid development of information society, the performance of gas sensors is required to be higher. Nanomaterials or composite materials can improve the response characteristics of the sensor, which has become a research hotspot in this field. In this paper, a new method of electrospinning and hydrothermal synthesis was proposed, and the nanostructure ZnO was prepared on the substrate in situ. The morphologies and structures of ZnO nanoparticles and nanoparticles were obtained by changing the hydrothermal conditions. The reaction is carried out in water system without adding organic solvent and other additives. At the same time, it avoids high temperature burning and secondary dispersion of nanometer materials. The process is simple and easy, and has the advantage of green environmental protection. The PPy/ZnO nanocomposites were prepared by vapor phase polymerization on the surface of ZnO, and the morphology, composition and structure of the composites were characterized by Fesemer XRDX FT-IRHRTEM. The response characteristics of the composites to NH3 at room temperature were investigated, and the effects of ZnO morphology on the response characteristics of the composites were investigated. The results show that the composite of PPy and w PPy has the best response characteristics, its resistance to 10 ppm NH3 varies from 76 to 76, which is 30 times higher than that of PPy, and shows excellent selectivity and reproducibility at the same time. The research on the response mechanism of the composite shows that the good contact between the composite and the substrate, the high specific surface area caused by the nanostructure, and the p-n junction formed at the interface between PPy and nanometer ZnO all contribute to the improvement of the sensitivity of the complex. The formation of p-n junctions plays a key role. Poly (aniline) with different morphology and structure was prepared by post-doping method, rapid mixing method and polymer acid template method. The PANI/ZnO nanocomposites were prepared by immersing PANI on the surface of ZnO with different nanostructures or deposited on the surface of ZnO by solution and gas phase polymerization. The composition and morphology of PANI/ZnO nanocomposites were characterized. The room temperature response of PANI/ZnO nanocomposites to NH3 was investigated. The effects of morphology and preparation methods of ZnO nanostructures on the sensitive properties of ZnO nanocomposites were investigated. It is found that the PANI and ZnO nanocomposites have the highest response sensitivity, and the relative change of resistance to 10 ppm NH3 is as high as 2150, which is 10 times higher than that of PANI. At the same time, the complex has a very low detection limit of 5 ppb, excellent selectivity and good reproducibility. The gas-sensing response mechanism of the composite is discussed. It is considered that the nanostructure and the p-n junction structure formed between ZnO and PANI can significantly improve the sensitivity of the complex.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB34;TP212

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