【作者】 王俊生；

【导师】 张凤宝； 王纪孝；

【作者基本信息】 天津大学 ， 化学工程， 2009， 博士

【摘要】 聚苯胺具有许多优良的物理化学性能,有广阔的应用前景。作为一种新型的多功能材料,微/纳米结构的聚苯胺在科学和技术上引起了人们广泛的兴趣,设计简单、有效、可控性强的合成技术构建聚苯胺微/纳米结构已成为该领域的研究热点。本论文围绕聚苯胺微/纳米结构制备方法中存在的问题展开,研究了一系列简单、有效构建多种形貌聚苯胺微/纳米结构的方法,表征了产物聚苯胺的结构,提出了其形成机理。主要的研究内容如下:1.采用非模板化学氧化法,首次在水溶液体系中成功控制合成了聚苯胺纳米片、纳米纤维、纳米颗粒。结果表明,苯胺单体与对甲基苯磺酸之间的摩尔浓度比对聚苯胺纳米形貌有明显影响,通过控制苯胺单体与对甲基苯磺酸之间的摩尔浓度比能够调控聚苯胺的纳米形貌。提出了不同纳米结构聚苯胺的形成机理,并对其化学结构进行了表征。2.以过氧化苯甲酰为氧化剂,首次在乙醇溶液中制备了高纯度的聚苯胺纳米片。结果表明,溶剂的分子结构对聚苯胺纳米形貌有显著影响,当使用乙醇为溶剂时得到高纯度、高疏水性(水测试接触角为145°)的聚苯胺纳米片;使用水为溶剂时所合成的聚苯胺为纳米片及纳米颗粒的混合结构,具有亲水性。苯胺单体与对甲基苯磺酸浓度比对聚苯胺纳米形貌影响显著。3.采用原位氧化聚合法,首次在含有聚乙烯醇的水溶液中将聚苯胺纳米片组装成聚苯胺纳米纤维。提出了聚苯胺纳米纤维的形成机理。结果表明,增加水溶液中苯胺中性分子的含量,降低反应物在溶液中的扩散速度有利于聚苯胺纳米纤维的形成。在聚乙烯醇存在的聚合体系中,聚苯胺的微观形貌受盐酸浓度及温度的影响显著。4.首次采用非模板化学法,通过控制溶剂组成,成功将聚苯胺纳米纤维组装成为海胆状聚苯胺微米球。得到的聚苯胺微米球直径在5-10μm之间,微球表面生长的纤维长度大约为1μm,直径大约30 nm,形如“海胆毛刺”。乙醇与水的体积比对聚苯胺微/纳米结构的形成具有明显的影响。分析了在苯胺聚合过程中产物微观形貌以及溶液pH值随时间的变化,提出了海胆状微米球的形成机理。更多还原

【Abstract】 As an inherent conducting polymer, polyaniline (PANI) has attracted considerable attention because of its unique doping/dedoping process, good optical and electrical properties, as well as excellent environmental stability. The design and synthesis of PANI nanostructures have received great attention in nanoscience and nanotechnology based on their unique properties and potential applications. Therefore, developing a facile, efficient, and controlable process to construct PANI micro/nanostructures is desirable.The research of this dissertation is focused on the issues of new methods to synthesize PANI with various micro/nanostructures. The structures and formation mechanism of PANI micro/nanostructures are also investigated. The main contents are listed:1. Polyaniline nanostructures with sheet-, fiber- and particle-like morphologies are synthesized controllablely from p-toluene sulfonic acid (p-TSA) aqueous solution. The results demonstrate that the morphology of PANI nanostructures is significantly influenced by the molar ratio of aniline to p-TSA. The morphology of PANI can be controlled by adjusting the molar ratio of aniline to p-TSA. A rational mechanism based on the self-assembly of micelles is proposed for the formation of PANI nanostructures. Fourier transform infrared, UV-visible spectroscopy and X-ray diffraction are applied to characterize the products.2. Exclusive sheet-like PANI is successfully synthesized in ethanol solution by a template-free process using benzoyl peroxide as oxidant. Solvent plays an important role in the formation of exclusive PANI nanosheets. When the solvent is changed from water to ethanol, PANI nanosheets are obtained exclusively and the wettability of the surface constructed by PANI nanosheets changes obviously, which changes from hydrophilic to super-hydrophobic (with water contact angle of 145.0o).3. Polyaniline nanofibers accumulated by flake-like PANI are assembled in the presence of polyvinyl alcohol (PVA) in aqueous solution. Based on the experimental results, a formation mechanism of PANI nanofibers is proposed. The experimental results indicate that increasing the amount of aniline neutral molecules and decreasing the diffusion rate of reactive substances are benefit for the formation of PANI nanofibers. The morphology of PANI is significantly influenced by the concentration of HCl and the solution temperature. 4. Urchin-like polyaniline microspheres with an average diameter of 5-10μm have been successfully prepared by a template-free method. The surface of the obtained microspheres consists of highly oriented nanofibers with about 30 nm in diameter and 1μm in length as characterized by scanning electron microscopy and transmission electron microscope techniques. The experimental results indicate that the solvent composition plays an important role in the formation process of urchin-like PANI microspheres. Based on the experimental results, the formation mechanism of PANI microspheres is proposed.更多还原