Size-Controlled Synthesis of Monodispersed Silver Nanoparticles Capped by Long-Chain Alkyl Carboxylates from Silver Carboxylate and Tertiary Amine
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- 作者：Mari Yamamoto ; Yukiyasu Kashiwagi ; Masami Nakamoto
- 刊名：Langmuir
- 出版年：2006
- 出版时间：September 26, 2006
- 年：2006
- 卷：22
- 期：20
- 页码：8581 - 8586
- 全文大小：418K
- 年卷期：v.22,no.20(September 26, 2006)
- ISSN：1520-5827
文摘
Monodispersed silver nanoparticles capped by long-chain alkyl carboxylates were prepared by the reaction of silvercarboxylate with tertiary amine at 80 
C for 2 h. This approach is a unique, size-controlled synthetic method for thelarge-scale preparation of silver nanoparticles. Long-chain alkyl carboxylate derived from a precursor acts as a stabilizerto avoid the aggregation of silver nanoparticles and to control particle size. In addition, amine plays an important roleboth as a reagent to form a thermally unstable, amine-coordinated intermediate, bis(amine)silver(I) carboxylate, andas a mild reducing agent for the intermediate to produce nanoparticles at a low temperature. The silver core andcarboxylate-capping ligand of silver nanoparticles were characterized by various techniques such as transmissionelectron microscopy, optical absorption spectroscopy, powder X-ray diffraction, X-ray photoelectron spectroscopy,gas chromatograph mass spectroscopy, and thermogravimetric and differential thermal analysis. The diameter of thenanoparticles can be strongly influenced by the alkyl chain length and the structure of the carboxylate. The averagediameters of the silver nanoparticles were controlled to less than 5 nm in the case of silver carboxylate with a singlealkyl chain length of 13 or 17 carbon atoms. On the contrary, the average diameters of silver nanoparticles becamelarge and polydisperse in the case of silver carboxylate with a chain length of 7 carbon atoms or a branched chain.In comparing triethylamine with trioctylamine, there was no obvious effect to regulate the size distribution of thenanoparticles because they could not function as a capping ligand of the nanoparticles due to their weak coordinationto silver. In addition, the heat treatment of silver nanoparticles in solution rather than in the solid state was effectivefor the growth of particles while maintaining narrow size distributions.
C for 2 h. This approach is a unique, size-controlled synthetic method for thelarge-scale preparation of silver nanoparticles. Long-chain alkyl carboxylate derived from a precursor acts as a stabilizerto avoid the aggregation of silver nanoparticles and to control particle size. In addition, amine plays an important roleboth as a reagent to form a thermally unstable, amine-coordinated intermediate, bis(amine)silver(I) carboxylate, andas a mild reducing agent for the intermediate to produce nanoparticles at a low temperature. The silver core andcarboxylate-capping ligand of silver nanoparticles were characterized by various techniques such as transmissionelectron microscopy, optical absorption spectroscopy, powder X-ray diffraction, X-ray photoelectron spectroscopy,gas chromatograph mass spectroscopy, and thermogravimetric and differential thermal analysis. The diameter of thenanoparticles can be strongly influenced by the alkyl chain length and the structure of the carboxylate. The averagediameters of the silver nanoparticles were controlled to less than 5 nm in the case of silver carboxylate with a singlealkyl chain length of 13 or 17 carbon atoms. On the contrary, the average diameters of silver nanoparticles becamelarge and polydisperse in the case of silver carboxylate with a chain length of 7 carbon atoms or a branched chain.In comparing triethylamine with trioctylamine, there was no obvious effect to regulate the size distribution of thenanoparticles because they could not function as a capping ligand of the nanoparticles due to their weak coordinationto silver. In addition, the heat treatment of silver nanoparticles in solution rather than in the solid state was effectivefor the growth of particles while maintaining narrow size distributions.