基于界面共价键构建的聚苯胺/多维碳基纳米结构体杂化电致变色材料

Electronic conduction (Conduction) and ionic transportation (Mass transfer) are the major important physical processes during the operation of electrochromic device. In this project, polyaniline and carbon nanostructures are connected via the interfacial covalent bond to enhance the conduction and mass transfer processes through improving the electronic conduction between these two phases and modulating the aggregation structures of polyaniline. The improved performances of electrochromic device are expected. In a typical experimental, the electrochromic hybrids are prepared through grafting the polyaniline onto three kinds of various dimensional carbon nanostructures. Due to the multi-dimensional structures and unique conductivities of carbon nanostructures, and their strong π-π interaction with polyaniline, the prepared hybrids possess high conductivity and loose aggregation structures. Using our proposed strategy, the dense molecular arrangement of polyaniline will be prohibited by interfacial covalent bond and the ionic transportation channel will be provided. The high electrochromic performances, e.g., fast response speed, high contrast and good long term stability of the hybrids will be achieved through enhancing the structure stability of polyaniline during its redox process and improving the electronic conduction of two conjugated systems. The influences of various dimension of carbon nanostructures on the aggregation structures, morphologies and ionic transportation of polyaniline will be investigated. Futhermore, the electronic conduction process between two phases of hybrids will be discussed to study the enhancement mechanism of the electrochromic properties of polyaniline. This work can perfect the theoretical basis of the relationship between the structures and the electrochromic properties of conducting polymer, which is significant for the practical application of conducting polymer based electrochromic materials.

电子传导（传导）和离子传输（传质）是电致变色器件工作过程中最重要的两大物理过程。本项目以界面共价键将聚苯胺与碳基纳米结构体进行联接，分别从促进两相间的电子传导和调控聚苯胺聚集态结构出发，同时改善传导和传质过程，达到提高器件性能的目的。具体实施过程是将苯胺分别接枝到三种不同维数的碳基纳米结构体上，利用碳纳米材料多维的纳米结构、优异的导电性及其与聚苯胺强的π-π相互作用，制备具有高电导率和疏松聚集态结构的杂化电致变色材料。利用界面共价键限制聚苯胺分子的紧密排列为离子传输提供通道，同时增强聚苯胺在氧化还原过程中的结构稳定性及促进两大共轭体系间的电子传导，提高变色材料的响应速度、对比度及长期工作稳定性。系统研究不同维数碳基纳米结构体对聚苯胺分子结构、聚集态结构和离子传输性能的影响；探讨两相界面间的电子传导对材料性能的促进机理。本项目可完善导电聚合物结构与变色性能的理论基础，对其实用化具有重要意义。

导电聚合物电致变色材料较差的长期工作稳定性是影响其大规模应用的关键因素。本项目将导电聚合物与不同维数的碳基纳米结构体进行共价键联接，利用碳基纳米结构体高电导率和与聚苯胺强的相互作用增强材料的电子传导过程；研究维数对聚苯胺分子结构、聚集态结构及离子传输性能的影响；分别改进影响电致变色材料工作的电子传导和离子传输过程来提高材料的变色性能；揭示材料结构与性能关系的共性问题。.主要结果与关键数据如下：.1.利用带有苯胺官能团的有机胺分别实现了对富勒烯、碳纳米管和石墨烯的功能化，再通过与苯胺进行共聚得到了一系列具有水溶性和油溶性的聚苯胺/碳基纳米结构体复合电致变色材料，对材料的结构、形貌和性能进行了表征。.2.不同维数碳基纳米结构体对聚苯胺的电子传导呈现一致性的增强作用，由于两者间强的π-π相互作用，复合材料的带隙随之变窄。但碳基纳米结构体对聚苯胺的离子传输的影响有所不同，其中零维的富勒烯及一维的碳纳米管加入后，复合材料中聚苯胺具有更疏松的分子排列，其离子传输过程更容易进行；但二维的石墨烯会因为其片层结构阻碍离子传输，随着添加量增加，离子传输性能变差。.3.由于碳基纳米结构体对复合材料电子传导和离子传输过程的促进作用，复合材料呈现出增强的电致变色性能。其中聚苯胺/富勒烯较纯聚苯胺离子电导率提高10余倍，对比度提高24%，着色效率提高35%；聚苯胺/碳纳米管较纯聚苯胺电荷转移电阻大幅下降，对比度提高38%，着色效率提高60%；聚苯胺/石墨烯较纯聚苯胺对比度提高36%，在低石墨烯含量时，响应速度随石墨烯含量增加而加快，但当石墨烯含量达到0.8%时，着色速度变慢。.4.聚苯胺/碳基纳米结构体复合材料相比于纯聚苯胺具有相对窄的带隙和较低的氧化电位，使得材料可在更低的电压下工作，避免了高工作电压可能带来的过氧化等副反应，由此组装的器件具有更高的长期工作稳定性。.本项目进一步完善了导电聚合物各级结构与其变色性能间构效关系的理论基础，对其实用化具有重要意义。