L-缬氨酸辅助合成聚苯胺花状纳米结构的机理研究
发布时间：2018-09-18 19:59
【摘要】：有机导电高分子材料在太阳能电池、发光二极管、气敏传感器以及可控电极方面有广泛的应用。和无机材料相比,它们具有优良的加工性,质子酸的可掺杂性以及环境稳定性的特点,而且它的物理和化学稳定性又可以通过其分子层面的设计来调控。但是目前用有机导电高分子材料组装的器件它的性能表现次于用无机材料组装的,其主要原因就是由于在分子、原子层面上研究高分子聚合原理的匮乏。本论文主要是以导电高分子聚苯胺(PANI)为模型,采用自组装法合成三维花状纳米结构的聚苯胺并利用核磁共振原位追踪技术(NMR)追踪整个反应过程,同时再利用透射电子显微镜(TEM)和扫描电子显微镜(SEM)进行直观的佐证,深入分析形成三维花状纳米结构聚苯胺的机理和可能原因。本论文不仅充实了从分子层面研究聚合物聚合体系,而且还为利用核磁共振技术从分子层面研究材料的形成机理奠定了基础。本论文主要开展了以下几方面的工作:1)以L-缬氨酸为掺杂酸,用自组装法制备三维花状纳米结构聚苯胺,研究主要内容为反应条件对产物结构的影响规律。研究表明,随反应中L-缬氨酸的含量增加,所制备的纳米聚苯胺依次呈现薄片状,花状以及带绒毛的片状形貌;采用甘氨酸(与L-缬氨酸分子结构相比缺少疏水链)作掺杂酸,对比研究发现了氨基酸和苯胺在未加APS时的初始缔和状态。2)为进一步理解三维花状纳米聚苯胺的成核机理,利用核磁共振原位追踪技术和二维核磁实验技术,并结合TEM和SEM表征手段,对比花状与非花状纳米聚苯胺形成过程中原位追踪核磁共振氢谱及聚合后产物形貌的变化最终表明花状纳米聚苯胺的形成过程具有如下几个典型特点:①反应初期由于L-缬氨酸具有酸碱两性,作为缓冲试剂可以有效调节苯胺单体的质子化程度,从而实现苯胺单体邻、对位电子云密度与间位的电子云密度接近,最终有利于聚合反应主要生成具有吩嗪结构的寡聚物;②反应前苯胺单体首先与缬氨酸形成较为稳定的胶束体系,继而反应产生的寡聚物在胶束内发生聚集,随后通过胶束融合过程进一步导致寡聚物聚集体成长为基本结构组装单元,在这些过程中处于胶束外层的缬氨酸分子始终起到稳定胶束与协调胶束融合的作用,导致组装过程最终形成热力学稳定产物。3)考虑到片状以及花状聚苯胺的堆积方式,具有较大的比表面积,而且通过机理研究发现寡聚物结构中存在大量的π-π重叠的共轭结构,电子离域程度较高,故推测其电化学性能较好。所以对合成的片状和花状结构的聚苯胺进行了电化学性能测试,主要运用了循环伏安法(CV)测试和充放电性能测试,研究结果表明花状结构的聚苯胺比片状具有更优越的电化学性能,并也有一定的电容性能但仍还需改性进一步优化提升。
[Abstract]:Organic conductive polymer materials are widely used in solar cells, light-emitting diodes, gas sensors and controllable electrodes. Compared with inorganic materials, they have excellent processability, proton acid doping and environmental stability, and their physical and chemical stability can be regulated by their molecular design. However, the performance of the devices assembled with organic conductive polymer materials is inferior to that of inorganic materials. The main reason is the lack of research on the principle of polymer polymerization on the molecular and atomic level. In this thesis, three dimensional Polyaniline with flower-like nanostructure was synthesized by self-assembly using conductive Polyaniline (PANI) as a model, and the whole reaction process was traced by (NMR). At the same time, transmission electron microscope (TEM) and scanning electron microscope (SEM) were used to prove the mechanism and possible causes of the formation of three-dimensional flower-like nanostructure Polyaniline. This thesis not only enriches the study of polymer polymerization system at molecular level, but also lays a foundation for studying the formation mechanism of materials at molecular level by nuclear magnetic resonance (NMR). In this paper, the following work was carried out: 1) Three-dimensional flower-like Polyaniline was prepared by self-assembly method with L-valine as the doped acid. The main content of this study was the influence of reaction conditions on the structure of the product. The results showed that with the increase of Lvaline content in the reaction, the prepared nano-Polyaniline showed flake, flower-like and fluffy morphology in turn, and glycine (lacking hydrophobic chain compared with Lvaline molecular structure) was used as the doped acid. It was found that the initial association and state of amino acid and aniline without APS) were used to further understand the nucleation mechanism of three-dimensional flower-like nano-Polyaniline. NMR in situ tracing technique and two-dimensional NMR technique were used to study the nucleation mechanism of aniline. Combined with TEM and SEM characterization, The in situ tracing of nuclear magnetic resonance (NMR) spectra and the morphologies of the polymerized products during the formation of flower-like and non-flower-like nano-Polyaniline showed that the formation process of the flower-like nano-Polyaniline was characterized by the following typical characteristics: 1: 1 initial reaction Because L-valine is acid-base amphoteric, As a buffer agent, the protonation degree of aniline monomer can be adjusted effectively, so that the para-potential electron cloud density is close to that of the m-position electron cloud, so that the oligomer with phenazine structure is mainly formed in the polymerization reaction. (2) aniline monomer first formed a stable micellar system with valine before the reaction, and then the oligomers produced by the reaction gathered in the micelle. Subsequently, through micellar fusion process, the oligomer aggregates grow into basic structural assembly units. In these processes, valine molecules in the outer layer of micelles always play the role of stabilizing micelles and coordinating micelle fusion. As a result of the final formation of thermodynamically stable product .3) considering the stacking patterns of floral and floral Polyaniline, it has a large specific surface area, and it is found that there are a large number of 蟺-蟺 overlapping conjugated structures in the oligomer structure. Due to the high degree of electron delocalization, it is assumed that its electrochemical performance is better. Therefore, the electrochemical properties of Polyaniline with floral and floral structures were tested, mainly by cyclic voltammetry (CV) and charge-discharge test. The results show that Polyaniline with flower-like structure has better electrochemical performance than flaky Polyaniline, and also has some capacitance properties, but it still needs to be optimized and upgraded by modification.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O633.21
本文编号：2248969
[Abstract]:Organic conductive polymer materials are widely used in solar cells, light-emitting diodes, gas sensors and controllable electrodes. Compared with inorganic materials, they have excellent processability, proton acid doping and environmental stability, and their physical and chemical stability can be regulated by their molecular design. However, the performance of the devices assembled with organic conductive polymer materials is inferior to that of inorganic materials. The main reason is the lack of research on the principle of polymer polymerization on the molecular and atomic level. In this thesis, three dimensional Polyaniline with flower-like nanostructure was synthesized by self-assembly using conductive Polyaniline (PANI) as a model, and the whole reaction process was traced by (NMR). At the same time, transmission electron microscope (TEM) and scanning electron microscope (SEM) were used to prove the mechanism and possible causes of the formation of three-dimensional flower-like nanostructure Polyaniline. This thesis not only enriches the study of polymer polymerization system at molecular level, but also lays a foundation for studying the formation mechanism of materials at molecular level by nuclear magnetic resonance (NMR). In this paper, the following work was carried out: 1) Three-dimensional flower-like Polyaniline was prepared by self-assembly method with L-valine as the doped acid. The main content of this study was the influence of reaction conditions on the structure of the product. The results showed that with the increase of Lvaline content in the reaction, the prepared nano-Polyaniline showed flake, flower-like and fluffy morphology in turn, and glycine (lacking hydrophobic chain compared with Lvaline molecular structure) was used as the doped acid. It was found that the initial association and state of amino acid and aniline without APS) were used to further understand the nucleation mechanism of three-dimensional flower-like nano-Polyaniline. NMR in situ tracing technique and two-dimensional NMR technique were used to study the nucleation mechanism of aniline. Combined with TEM and SEM characterization, The in situ tracing of nuclear magnetic resonance (NMR) spectra and the morphologies of the polymerized products during the formation of flower-like and non-flower-like nano-Polyaniline showed that the formation process of the flower-like nano-Polyaniline was characterized by the following typical characteristics: 1: 1 initial reaction Because L-valine is acid-base amphoteric, As a buffer agent, the protonation degree of aniline monomer can be adjusted effectively, so that the para-potential electron cloud density is close to that of the m-position electron cloud, so that the oligomer with phenazine structure is mainly formed in the polymerization reaction. (2) aniline monomer first formed a stable micellar system with valine before the reaction, and then the oligomers produced by the reaction gathered in the micelle. Subsequently, through micellar fusion process, the oligomer aggregates grow into basic structural assembly units. In these processes, valine molecules in the outer layer of micelles always play the role of stabilizing micelles and coordinating micelle fusion. As a result of the final formation of thermodynamically stable product .3) considering the stacking patterns of floral and floral Polyaniline, it has a large specific surface area, and it is found that there are a large number of 蟺-蟺 overlapping conjugated structures in the oligomer structure. Due to the high degree of electron delocalization, it is assumed that its electrochemical performance is better. Therefore, the electrochemical properties of Polyaniline with floral and floral structures were tested, mainly by cyclic voltammetry (CV) and charge-discharge test. The results show that Polyaniline with flower-like structure has better electrochemical performance than flaky Polyaniline, and also has some capacitance properties, but it still needs to be optimized and upgraded by modification.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O633.21
【参考文献】
相关期刊论文 前3条
1 高莹丽;王瑞娟;刘空;武晓东;;利用核磁共振技术研究聚苯胺纳米棒的成核机理[J];广州化工;2015年17期
2 ;Gas sensing performance of polyaniline/ZnO organic-inorganic hybrids for detecting VOCs at low temperature[J];Journal of Natural Gas Chemistry;2011年05期
3 许新华;姜胜天;刘新友;张国平;;酚与4,4′-联吡啶π-π叠加作用的核磁氢谱研究[J];湖南大学学报(自然科学版);2007年06期
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