Thermal Percolation in Stable Graphite Suspensions

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• 作者：Ruiting Zheng ; Jinwei Gao ; Jianjian Wang ; Shien-Ping Feng ; Hiroko Ohtani ; Jinbo Wang ; Gang Chen
• 刊名：Nano Letters
• 出版年：2012
• 出版时间：January 11, 2012
• 年：2012
• 卷：12
• 期：1
• 页码：188-192
• 全文大小：432K
• 年卷期：v.12,no.1(January 11, 2012)
• ISSN：1530-6992

文摘

Different from the electrical conductivity of conductive composites, the thermal conductivity usually does not have distinctive percolation characteristics. Here we report that graphite suspensions show distinct behavior in the thermal conductivity at the electrical percolation threshold, including a sharp kink at the percolation threshold, below which thermal conductivity increases rapidly while above which the rate of increase is smaller, contrary to the electrical percolation behavior. Based on microstructural and alternating current impedance spectroscopy studies, we interpret this behavior as a result of the change of interaction forces between graphite flakes when isolated clusters of graphite flakes form percolated structures. Our results shed light on the thermal conductivity enhancement mechanisms in nanofluids and have potential applications in energy systems.

Keywords:

Thermal; percolation; graphite; suspension