Chen X P, Liang Q H, Jiang J K, Wong Cell K Y, Leung Stanley Y Y, Ye H Y, Yang D G, Ren T L
Key Laboratory of Optoelectronic Technology &Systems, Education Ministry of China, Chongqing University and College of Opto-electronic Engineering, Chongqing University, Chongqing 400044, China.
Faculty of Electromechanical Engineering, Guilin University of Electronic Technology, 541004 Guilin, China.
Sci Rep. 2016 Feb 9;6:20621. doi: 10.1038/srep20621.
In this paper, we present a first-principles and molecular dynamics study to delineate the functionalization-induced changes in the local structure and the physical properties of amorphous polyaniline. The results of radial distribution function (RDF) demonstrate that introducing -SO3(-)Na(+) groups at phenyl rings leads to the structural changes in both the intrachain and interchain ordering of polyaniline at shorter distances (≤5 Å). An unique RDF feature in 1.8-2.1 Å regions is usually observed in both the interchain and intrachain RDF profiles of the -SO3(-)Na(+) substituted polymer (i.e. Na-SPANI). Comparative studies of the atom-atom pairs, bond structures, torsion angles and three-dimensional structures show that EB-PANI has much better intrachain ordering than that of Na-SPANI. In addition, investigation of the band gap, density of states (DOS), and absorption spectra indicates that the derivatization at ring do not substantially alter the inherent electronic properties but greatly change the optical properties of polyaniline. Furthermore, the computed diffusion coefficient of water in Na-SPANI is smaller than that of EB-PANI. On the other hand, the Na-SPANI shows a larger density than that of EB-PANI. The computed RDF profiles, band gaps, absorption spectra, and diffusion coefficients are in quantitative agreement with the experimental data.
在本文中，我们开展了一项第一性原理和分子动力学研究，以描绘非晶态聚苯胺中官能团化诱导的局部结构变化和物理性质。径向分布函数（RDF）的结果表明，在苯环上引入-SO3(-)Na(+)基团会导致聚苯胺在较短距离（≤5 Å）内链内和链间有序性的结构变化。在-SO3(-)Na(+)取代聚合物（即Na-SPANI）的链间和链内RDF曲线中，通常会在1.8 - 2.1 Å区域观察到一个独特的RDF特征。对原子对、键结构、扭转角和三维结构的比较研究表明，EB-PANI的链内有序性比Na-SPANI好得多。此外，对带隙、态密度（DOS）和吸收光谱的研究表明，环上的衍生化不会实质性改变聚苯胺固有的电子性质，但会极大地改变其光学性质。此外，计算得到的水在Na-SPANI中的扩散系数小于EB-PANI中的扩散系数。另一方面，Na-SPANI的密度比EB-PANI大。计算得到的RDF曲线、带隙、吸收光谱和扩散系数与实验数据在定量上一致。
