聚苯胺/磷酸盐杂化电活性离子交换功能膜的结构调控与界面电荷传递

The objective of the present research is to synthesize, characterize and investigate efficiencies of novel hybrid nano-composite electroactive materials for the application of electrochemically switched ion exchange in aqueous solution. In this proposal, the hybrid ployaniline/metal phosphate (PANI/MP) nanocomposite film, will be fabricated via a novel electrodeposition method to embed organic polymer PANI into the matrices of the inorganic precipitate of MP. By the aid of the transfer of proton (contained in solid acid MP) inside the organic/inorganic hybrid system, an acidic micro-environment could be provided for the nitrogen atom in PANI chains, maintaining its electroactivity in neutral aqueous solution. By regulating the redox states of the hybrid film, ion-exchange between the solution and hybrid electroactive material could be driven and controlled. Therefore, this novel class of hybrid material should have excellent function of electrochemically switched ion exchange in the neutral media. Structural attributes of the ion-exchange functional unit in the hybrid material will be designed and suitable electrochemical synthesis route will be optimized based on the traits of the target ion. It is expected that the hybridization of organic and inorganic electroactive ion-exchange functional material is performed in the molecular and/or lattice scale, and a stable film with a three dimensional porous ordered network is formed at a sub-micro scale. Interlayer spacing will be tuned by intercalating aniline into nano-sheets of the layered phosphate and by controlling the polymerization rate of the polyaniline during the synthesis process. The relationship among the composition, structure and ion exchange ability of the hybrid films will be also investigated in order to realize the diversity and controllability of the structure with respect to the function of the hybrid film. Furthermore, the interface charge transfer mechanism and hybridization principle of the three dimensional structural hybrid films, and their relationships with the structural characteristics and the stability of the hybrid interface in nano-submicro scale will be elucidated. Research results are expected to provide theoretical basis for the structure design of this novel kind of hybrid electroactive film with an excellent electrochemically switched ion-exchange performance.

本项目以导电聚苯胺和固体酸磷酸盐杂化体系为研究对象，借助固体酸中所含质子在有机/无机杂化体系内部传递形成满足聚苯胺导电的酸性微环境，通过调节杂化膜的氧化还原状态驱动并控制溶液和杂化电活性材料之间的离子交换，使这一类新型杂化材料在非酸性介质中具备电控离子交换功能。根据目标离子的特性来设计杂化膜离子交换功能基元的结构属性和适宜的电化学合成路线，实现分子或晶格尺度上有机和无机电活性离子交换功能材料的杂化，在亚微米尺度上形成稳定的三维多孔有序网络状结构。合成过程中通过在层状磷酸盐层板间插入苯胺并控制聚合速率对层间距进行调控，分析揭示杂化膜中元素组成、结构特征与离子交换性能之间的关系，从而实现杂化膜结构和功能的多样性及可控性。重点研究纳米-亚微米尺度下三维结构杂化膜的界面电荷传递机理、杂化原理、杂化界面的结构特征和结构稳定性，为新型杂化电活性离子交换功能膜的结构和性能设计提供理论依据和参考。

能源和环境问题正日益成为人们关注的焦点，而电活性材料（EM）由于在储能器件、环境检测传感器、离子分离、电催化以及控制释放等新技术领域有着广阔的应用前景而引起研究者们的广泛兴趣。其中电活性离子交换材料（EIXM）是离子-电子的混合导体，具有独特的电化学转换离子交换功能，相关EIXM材料合成、结构和性能研究已成为当前国际上的研究热点，而针对特定目标离子进行选择性分离，研发新一代电活性杂化离子交换功能膜已成为EM发展的关键。.本项目以导电聚苯胺和固体酸磷酸盐杂化体系为研究对象，借助固体酸中所含质子在有机/无机杂化体系内部传递形成满足聚苯胺导电的酸性微环境，通过调节杂化膜的氧化还原状态驱动并控制溶液和杂化电活性材料之间的离子交换，使这一类新型杂化材料在非酸性介质中具备电控离子交换功能。根据目标离子的特性设计了杂化膜离子交换功能基元的结构属性并筛选了适宜的电化学合成路线，在分子或晶格尺度上实现了有机和无机电活性离子交换功能材料的杂化，在亚微米尺度上形成了稳定的三维多孔有序网络状结构。通过在层状磷酸盐层板间插入苯胺并控制聚合速率对层间距进行调控，或在碳纳米管（低聚体聚苯胺）修饰电极上可控合成无定型α-磷酸锆/聚苯胺杂化膜，分析揭示杂化膜中元素组成、结构特征与离子交换性能之间的关系，从而实现杂化膜结构和功能的多样性及可控性。重点研究了纳米-亚微米尺度下三维结构杂化膜的界面电荷传递机理、杂化原理、杂化界面的结构特征和结构稳定性，为新型杂化电活性离子交换功能膜的结构和性能设计提供理论依据和参考。.在乙腈溶液中采用单极脉冲电沉积方法合成了一种新颖的具有电位响应金属离子交换性能的α-磷酸锆/聚苯胺插层膜，在中性介质中利用杂化膜内部的质子自交换实现了对镍离子的选择性分离。杂化膜对镍离子的平衡吸附量达到109mg/g，拟一级吸附动力学常数达到0.0124/s，其吸脱附速率是传统材料的10倍。在水相中通过两步法在低聚体PANI上接枝合成了无定型α-磷酸锆/聚苯胺多孔纤维膜，该杂化膜对Pb离子的平衡吸附量达到123.5mg/g，1000次循环其离子交换容量保持在85.2%。.本项目针对PANI/MP杂化膜电极的制备方法及其结构调控和电荷传递性能进行研究，获得了一种质子内部自交换机制的新型杂化电控离子交换膜，在理论上有突出的创新，其科学价值和应用价值是非常显著的。