Two-Dimensional Pressure-Driven Nanorod-to-Nanowire Reactions in Langmuir Monolayers at Room Temperature
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- 作者：Somobrata Acharya and Shlomo Efrima
- 刊名：Journal of the American Chemical Society
- 出版年：2005
- 出版时间：March 16, 2005
- 年：2005
- 卷：127
- 期：10
- 页码：3486 - 3490
- 全文大小：470K
- 年卷期：v.127,no.10(March 16, 2005)
- ISSN：1520-5126
文摘
Typical two-dimensional surface pressures prevalent within floating monolayer (Langmuir) filmsare on the order of a few dozen megapascals. One might expect, therefore, that some chemical reactionsshould be directly and strongly affected by this surface pressure, along with the well-known effect of pressureon the orientational order and the mere proximity of the molecules within the film. Here, we show that thetwo-dimensional surface pressure in Langmuir films provides a direct driving force, decreasing the activationenergy of a cooperative oriented coalescence of ZnS nanorods into nanowires near room temperature. Atlow film surface pressure or low temperature, the nanorods do not react, while in solution, they react onlyabove 140 
C, even though in all of these cases, the rods are organized in similar super-crystalline clusters.Electron microscopy and measurements of the reaction rates give a detailed picture of the order of therods, their rearrangement, and their coalescence.
C, even though in all of these cases, the rods are organized in similar super-crystalline clusters.Electron microscopy and measurements of the reaction rates give a detailed picture of the order of therods, their rearrangement, and their coalescence.