Acta Chimica Sinica ›› 2013, Vol. 71 ›› Issue (07): 999-1006.

Review

### 聚苯胺在高pH值溶液中的电化学活性

1. 南京理工大学软化学与功能材料教育部重点实验室 南京 210094
• 投稿日期:2013-02-02 发布日期:2013-05-16
• 通讯作者: 宋晔, E-mail: soong_ye@sohu.com E-mail:soong_ye@sohu.com
• 作者简介:宋晔, 博士, 南京理工大学高分子材料与工程专业副教授. 1994 年从西安交通大学硕士毕业后, 分配至南京理工大学从事教学科研工作至今. 目前主要从事导电聚苯胺纳米结构制备及其电化学性能研究.
• 基金资助:

项目受国家自然科学基金(Nos. 51077072, 61171043)资助.

### Electroactivity of Polyaniline in High pH Solutions

Song Ye, Lv Huiling, Hu Songwei, Yang Chunyan, Zhu Xufei

1. Key Laboratory of Soft Chemistry and Functional Materials of Education Ministry, Nanjing University of Science and Technology, Nanjing 210094
• Received:2013-02-02 Published:2013-05-16
• Supported by:

Project supported by the National Natural Science Foundation of China (Nos. 51077072, 61171043).

Generally, the redox activity of polyaniline (PANI) can only be retained in acidic media at pH<4, because the occurrence of deprotonation of the nitrogen atoms in the PANI backbone at high pH values may result in the loss of conductivity and electroactivity in neutral or alkaline solutions. This high acidity requirement greatly limits its potential applications like biosensor, marine antifouling and anticorrosion, where neutral or alkaline environments must be faced. Much effort has been exerted in the development of approaches to overcome this issue. In summary, two principal strategies have been proposed to shift the electroactivity of PANI to a high pH environment. One is based on a mechanism of protonic acid doping, the other is based on a charge transfer process. The former is to introduce acidic groups into the PANI chains or PANI systems to hinder the deprotonation of its conducting form and thus to preserve its electroactivity at higher pH values. The main approaches to introduction of acidic groups include the sulfonation of the emeraldine base of PANI, the homopolymerization of aniline derivatives with acidic ionogenic groups or the copolymerization of aniline and aniline derivatives, and the formation of PANI complexes by doping with macromolecular acids. The latter is to use a hybrid film fabricated by incorporating conductive nanomaterials into a PANI matrix, which can improve the charge transfer rate across the PANI matrix and facilitate its redox processes. The development of PANI nanocomposites prepared by doping with carbon nanotubes, graphenes and Au nanoparticles, etc., falls into this category. This review article provides an overview of various approaches to preserve the electroactivity of PANI in high pH solutions on the basis of the two main strategies. Special emphasis is placed on the synthetic methods and electrochemical features for the self-doped, polymer acid-doped and CNT-doped PANIs, including their underlying mechanisms for achieving good electroactivity. The main challenges and future research directions in this field are also discussed.