【作者】 张龙；

【导师】 刘鹏；

【作者基本信息】 兰州大学 ， 高分子化学与物理， 2011， 博士

【摘要】 高分子材料起初被认为是不导电的,直到导电聚乙炔的出现,这一概念才得以转变。按电导率的高低可把材料分为超导体、导体、半导体和绝缘体四种类型。而导电高分子材料的电导率,可以跨越导体和绝缘体。导电高分子材料的电导率范围跨度如此之大,是其他金属材料和无机非金属材料无法比拟的,它们已经成为科学技术和经济建设中的重要材料。随着聚苯胺导电性能的发现,由于其合成方法简便、化学稳定性好、可方便的进行掺杂与解掺杂等特性,被认为是最有可能进行大规模应用的结构型导电高分子。然而,聚苯胺分子结构中有大量的苯式结构和醌式结构,这些结构使得聚苯胺分子呈刚性,因而聚苯胺被认为是不溶解不熔融的,这便极大地限制了聚苯胺的应用范围。为了克服聚苯胺加工性能差的缺点,人们制备了各种形貌的聚苯胺,如纳米纤维、纳米管、纳米带、空心球等。具有规整形貌的聚苯胺与普通方法制备的非晶粉末状聚苯胺相比,不但其在一般溶剂中的分散性能有所提高,而且它的电性能也有极大地改善。论文的研究主要是为聚苯胺空心结构的构筑提供了一些思路和方法。这些思路和方法内容如下：(1)以天然埃洛石为模板制备了规整地聚苯胺纳米管。天然埃洛石具有管状结构,它的外层结构主要由Si02构成,而内层结构主要由A1203构成。因此,当以原位无皂乳液聚合法将聚苯胺包覆在埃洛石表面上后,用HCl/HF的混酸溶液可以将埃洛石刻蚀掉,从而得到聚苯胺纳米管状结构。超声作用在埃洛石吸附苯胺过程中起到重要作用,与搅拌作用相比超声作用可以有效地改善苯胺在埃洛石表面的包覆效果,并提升PANI/HNTs复合材料在水中的分散性。(2)以甲苯为软模板,以阴离子表面活性剂和磁性纳米颗粒可以为分散介质,通过结合界面聚合法和Pickering乳液法制备了具有电磁双重性能的聚苯胺磁性空心球。着重研究了磁性纳米颗粒的用量对磁性聚苯胺空心球形貌的影响。表面活性剂对最终聚苯胺空心球的尺寸有决定性作用,而磁性纳米颗粒在聚合过程中对胶束形貌有保护作用。甲苯在反应过程中既充当液滴模板的作用,又是苯胺单体的“储藏室”。(3)以长轴约50nm,短轴仅约为8nm的纺锤状Fe203为模板,用离子化的对氨基苯甲酸对纳米氧化铁进行修饰,制备了纺锤状聚苯胺空心结构。苯胺单体的用量对聚苯胺最终的形貌有很大的影响,只有当苯胺与模板的质量比为2：1时,才能形成完整地聚苯胺纺锤结构。当苯胺太少时聚苯胺不能完全包覆氧化铁,最终形成的聚苯胺空心结构上会有缺口,而当苯胺太多时又会使苯胺在水溶液中聚合形成聚苯胺团聚体,不利于聚苯胺的包覆。(4)在酸性条件下以纳米球状Fe203作为牺牲性模板和氧化剂制备了聚苯胺空心球。反应温度对聚苯胺最终的形貌有很大的影响,温度太低(如室温)不利于形成聚苯胺空心结构。同时还研究了质子酸的种类对制备聚苯胺空心球的效果的影响。(5)以Fe3O4@PS核壳结构为“部分可溶性模板”制备磁性聚苯胺复合材料。随引发剂的用量不同,所制备出的模板在苯胺溶胀聚合过程中被溶解的程度也有很大差别。当聚苯乙烯在低浓度引发剂条件下制得时,可制备出Fe3O4@PS@PANI三明治结构；当聚苯乙烯在高浓度引发剂条件下制得时,可制备出Fe3O4@PANI蛋黄结构。同时还发现随着引发剂浓度的增加,最终产物中开孔的尺寸也随之增大。文中讨论了孔形成的原理。更多还原

【Abstract】 It is thought that the polymer materials are not conductive, until the appearance of conducting polyacetylene. According to the level of conductivity, materials can be separated into four types: superconductor, conductor, semiconductor and insulator. Conductive polymers can change from insulator to conductor with changing the oxidation degree and doped level. The conductive polymers have become an important material in science, technology and economic construction for their changeable conductivity. With the discovery of conductivity of polyaniline, it is considered polyaniline is most likely to be large-scale application among the structured conductive polymers, due to their ease of processability, high environmental stability and special doping mechanism. However, the unsubstituted PANI is intractable and suffers from poor processability due to its rigid, highly conjugated backbones, which have hindered their application in many fields. To overcome this shortcoming, variety of morphologies of PANI (such as nanofibers, nanotubes and hollow microspheres) were prepared by changing the synthesis method. In addition, compared with random connected nanowires, well-ordered nanostructure can improve both the dispersion and electric property of polyaniline.This paper aims to provide some new ideas and methods to build polyaniline hollow constructs. These ideas and methods are as follows:(1)A template-based fabrication technique for PANI nanotubes with halloysite nanotubes (HNTs) as template. The HNTs associate the chemical properties of halloysite tubule’s outermost surface with the properties of SiO2 and properties of the inner cylinder core with Al2O3. So the PANI nanotubes were obtained by etching the template with HCl/HF solution after the PANI layers were coated onto the template via in situ soapless emulsion polymerization. The coated polyaniline layers prepared with ultrasonic irradiation were more symmetrical and the PANI/HNTs hybrids had the better dispersibilities in water than those from the adsorption with stirring, which were conglomeration.(2)An ingenious strategy for the synthesis of the magnetic PANI functional hollow microspheres is explored, which combines the interfacial polymerization and Pickering emulsion techniques in an 0/W emulsion system, with Fe3O4-CA nanoparticles as cosurfactant. The effect of the amount of Fe3O4-CA nanoparticles on the formation of integrated Fe3O4-CA-PANI hollow microspheres was investigated. The amount of surfactant plays an important role on maintaining the size of PANI capsules. Toluene acts as the role of "soft-template" and storage of monomer.(3)Rod-shaped polyaniline nanocapsules were prepared via the in-situ chemical oxidative polymerization of aniline with a-Fe2O3 nanorods about 50nm in length and about 8nm in width as templates after being modified with p-aminobenzoic acid ion. When the weight ratio of aniline/Fe2O3 nanorods of 2:1 was adopted, the uniform rod-shaped PANI nanocapsules with length and diameter of about 80 and 5 nm were achieved. Above or below this ratio will not get complete PANI capsules.(4)Hollow polyaniline nanoparticles were fabricated via the facile chemical oxidative polymerization of aniline with y-Fe2O3 nanoparticle as the reactive template in the presence of the protonic acid. The effects of the reaction temperature and the kind of the protonic acid used on the formation of the hollow nanostructures were discussed.(5)Fe3O4@PS nanoparticles were used as "partial sacrificial templates", during the oxidation polymerization partial or all of the polystyrene can be dissolved. When polystyrene was prepared with low concentration of initiator, sandwich Fe3O4@PS@PANi nanoparticles were obtained; when polystyrene was prepared with high concentration of initiator, yolk/shell Fe3O4@PANI structures were prepared; when polystyrene was prepared with middle concentration of initiator, different size of holes presented in final composites. As the concentration of initiator increased, the size of holes increased. The possible process of the formation of hole has been given.更多还原