【作者】 周志斌；

【导师】 张凤宝； 王纪孝；

【作者基本信息】 天津大学 ， 化学工程， 2010， 博士

【摘要】 材料的性能与应用不仅与化学组成、结构有关,还与组成材料的微观单元的尺寸和微观单元的堆积方式有密切关系。聚苯胺具有结构多样、掺杂机理独特、环境稳定性好、原料价廉及合成方法简便等优点,是导电聚合物的一个重要研究对象。制备和表征聚苯胺的微/纳米结构对控制它们的组装和调节聚苯胺的性能具有重要的理论意义和应用价值。本论文探讨了制备聚苯胺微/纳米结构的新方法,成功实现了不同聚苯胺微/纳米结构的可控生长,并将低维纳米结构组装成多尺度的微米结构。对聚苯胺微/纳米结构的分子结构、制备过程的影响因素、形成机理进行了研究和探讨。在硫酸溶液中,制备了聚苯胺纳米线形成的多尺度多孔微球,微球具有纯度高、形貌一致、粒度均匀、导电性良好、比表面积大、优异的亲水性等优点。苯胺浓度、苯胺与过硫酸铵的摩尔浓度比、聚合温度、酸度和聚合时间对聚苯胺微球的形成有重要影响。通过调节苯胺浓度、聚合温度可控制微球的平均直径,通过改变质子酸的种类和使用十二烷基苯磺酸钠可调节聚苯胺纳米线自组装形成的多尺度结构。向反应体系添加环氧丙烷,可改善在较高过硫酸铵浓度下制备的微球的形貌和粒径。氧化剂的种类对微球的形成无明显影响,但会影响微球的粒径分布。提出了聚苯胺纳米线自组装形成聚苯胺多尺度多孔微球的机理。结合自组装和原位法,制备了负载有金属银纳米颗粒的聚苯胺微球复合物。利用电化学氧化聚合苯胺后的电解液滤液制备了形貌均一、纯度高、结晶度高的聚苯胺纳米片。所制备的纳米片处于高氧化本征态、分子链排列有序、具有良好的疏水性等特点。电化学氧化聚合苯胺时电解液酸度、聚合时间、电化学参数对聚苯胺纳米片的形成有重要影响。改变电解液酸度、滤液的聚合温度和聚合时间可以调节纳米片的形状和侧向尺寸大小。提出了电解液滤液制备聚苯胺纳米片的形成机理,使用H2O2为氧化剂制备了模拟电解液滤液,并以此制备了高结晶度的聚苯胺纳米片。研究结果为电化学氧化聚合苯胺的电解液废液的再利用提供了依据。采用非模板自组装法制备聚苯胺微球和纳米片的方法,对于聚苯胺的应用和其他聚合物微、纳米材料的制备有重要的指导意义。聚苯胺微球和纳米片将分别在传感器、催化剂载体、固相分离和防腐蚀、自清洁表面等方面有着潜在的应用。更多还原

【Abstract】 Properties and applications of materials are not only determined by their composition and structure, but also the size of building blocks and their aggregation state. Due to its variable molecular structures, unique doping mechanism, good redox reversibility, excellent environmental stability, easy preparation and cost-effective raw materials, polyaniline (PANI) has been extensively investigated as an inherent conductive polymer in the last three decades. It is of great theoretical significance to prepare and characterize the PANI micro/nanostructures. This dissertation is focused on the issues of novel methods to prepare PANI with various micro/nanostructures, control their morphologies and size, and self-assembly of the nano-building blocks into hierarchical microstructures. The structures, formation mechanism and the influences of preparation parameters on the PANI micro/nanostructures are also investigated.PANI hierarchical porous microspheres self-assembled from PANI nanowires are prepared from the H2SO4 aqueous solution, which show relatively high conductivity, BET specific surface area and excellent hydrophilic behavior. The results demonstrate that the concentration of aniline, mole ratio of aniline to ammonium peroxydisulfate (APS), polymerization temperature, polymerization time, types of acid and the acidity have significant effect on the morphology of PANI product. The average diameter of the microspheres can be controlled by adjusting the concentration of aniline and polymerization temperature, and the hierarchical microstructures self-assembled from PANI nanowires can be controlled by types of acid and adding sodium dodecylbenzenesulphonate. The uniformity and size distribution of microspheres in the higher concentration of APS can be improved by adding propylene oxide. The oxidant kinds have no obvious effect on the microspheres; however, it will affect the diameter of the microspheres. The formation mechanism of hierarchical microstructures from PANI nanowires is proposed. The Ag-nanoparticle/PANI microcomposite is prepared by combining the self-assembly and in-suit method.High purity, uniformity and crystallinity of PANI nanosheets are prepared from the filtration, which comes from the electropolymerization of aniline. The as-prepared PANI nanosheets are in emeraldine state with the ordered polymer chains and good hydrophobic behavior. The acidity of the electrolyte, electropolymerization time, electrochemical parameters play important role in the formation of PANI nanosheets during the electropolymerization of aniline. The shapes and the lateral sizes of the nanosheets can be adjusted by the acidity of the electrolyte, polymerization temperature and time. A mechanism based on the self-assembly and oriented growth of aniline oligomers is proprosed for the formation of PANI nanosheets, and the higher crystallinity PANI nanosheets are synthesized from the analogue electrolyte prepared by using the H2O2 as oxidant. Meanwhile, it provides the guideline for the re-use of electrolyte of electropolymerization of aniline.The template-free self-assembly of PANI micro/nanostructures provides novel insight into preparation of other polymer micro/nanostructured materials. The PANI hierarchical porous microspheres and PANI nanosheets might have promising applications in the filed of sensor, catalysis support, solid separation and anti-corrosion, self-clean surface, respectively.更多还原