Formation process of silver-polypyrrole coaxial nanocables synthesized by redox reaction between AgNO3 and pyrrole in the presence of poly(vinylpyrrolidone).
Formation process of silver-polypyrrole coaxial nanocables synthesized by redox reaction between AgNO3 and pyrrole in the presence of poly(vinylpyrrolidone).
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DOI：
10.1021/jp053247x
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发表时间：
2005-09
期刊：
影响因子：
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通讯作者：
Aihua Chen;K. Kamata;M. Nakagawa;T. Iyoda;Haiqiao Haiqiao Wang-Haiqiao;Xiaoyu Li
中科院分区：
文献类型：
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作者：
Aihua Chen;K. Kamata;M. Nakagawa;T. Iyoda;Haiqiao Haiqiao Wang-Haiqiao;Xiaoyu Li
我们最近展示了一种一步制银聚吡啶（PPy）同轴纳米电缆（Chen, a .; Wang， H.; Li， X. Chem.）。common . 2005, 14, 1863)。本文讨论了银-聚吡啶共轴纳米电缆的形成过程。TEM和SEM结果表明，在吡咯溶液中加入AgNO3可形成大量银原子。然后，银原子转变为具有规则形态的银ppy纳米片，它们将连接在一起，从而更加稳定。银ppy纳米电缆将能够以牺牲银ppy纳米片为代价生长。聚乙烯吡咯烷酮（PVP）在这一过程中起着至关重要的作用：作为形成银纳米线的盖层剂，作为吡咯单体的分散剂，可以影响吡咯单体存在的位置。在实验分析的基础上，提出了可能的机理。由于PVP的作用，银离子和吡咯单体容易分别吸附在银纳米片的[111]和[100]面。在[111]和[100]面交界处会发生明显的聚合。PPy层在[100]面上保持稳定。同时，新形成的银原子和银纳米片将在[111]表面进一步成熟和生长。总之，最终产物的形态和形成过程取决于AgNO3与吡咯单体的反应位置，而反应位置又受PVP的影响。
We have recently demonstrated a one-step process to fabricate silver-polypyrrole (PPy) coaxial nanocables (Chen, A.; Wang, H.; Li, X. Chem. Commun. 2005, 14, 1863). The formation process of silver-PPy coaxial nanocables is discussed in this article. It was found from the results of TEM and SEM images that large numbers of silver atoms were formed when AgNO3 was added to a pyrrole solution. Then silver atoms transform to silver-PPy nanosheets with regular morphology, which will connect together to be more stable. Silver-PPy nanocables will be able to grow at the expense of the silver-PPy nanosheets. Poly(vinylpyrrolidone) (PVP) plays crucial roles in this process: as a capping agent to form silver nanowires, and as a dispersant of pyrrole monomers, which can influence the site at which pyrrole monomer exists. On the basis of experimental analysis, the possible mechanism was proposed. Because of the effect of PVP, silver ions and pyrrole monomers are apt to be adsorbed at the [111] and [100] facets of silver nanosheets, respectively. Obvious polymerization will take place on the boundary of the [111] and [100] facets. The PPy layer stays stable on the [100] facets. Meanwhile, newly formed silver atoms and silver nanosheets will further ripen and grow on the [111] facets. In a word, the morphology of final products and the formation process are determined by the reaction site between AgNO3 and the pyrrole monomer, which is influenced by PVP.