Theoretical and computational studies of carbon nanotube composites and suspensions: Electrical and thermal conductivity
Theoretical and computational studies of carbon nanotube composites and suspensions: Electrical and thermal conductivity
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DOI：
10.1103/physrevb.71.104201
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发表时间：
2005-03-01
影响因子：
3.7
通讯作者：
Sobolev, VL
中科院分区：
文献类型：
--
作者：
Foygel, M;Morris, RD;Sobolev, VL
已经进行了蒙特卡罗模拟，目的是找到与随机取向的纳米管(或者实际上，任何具有大长宽比的导电颗粒)随机分散在低热或导电介质中的渗流开始相关的临界分数体积(CFV)。纳米管被处理成具有高(直到2000)长宽比a的有盖的互穿导电圆柱体(“棒”)。已经发现，对于这些长宽比，CFV与a成反比，从而导致在这种体系中实现渗流所需的低得令人惊讶的0.01%的填充物体积负荷。通过研究CFV和渗流团簇密度的涨落，计算了渗流理论的各种临界指数，包括临界电导率指数t。对于三维体系，发现t随长宽比的增大而显著减小。计算的纳米管悬浮液和复合材料的热导率和电导率随纳米管负载量的变化与最近的实验数据符合得很好。
Monte Carlo simulations have been performed, aimed at finding a critical fractional volume (CFV) associated with the onset of percolation for randomly oriented nanotubes (or, indeed, any conductive particles with large aspect ratios) that are randomly dispersed in a low thermo- or electroconductive medium. The nanotubes were treated as capped interpenetrating conductive cylinders ("sticks") with high (up to 2000) aspect ratio a. It has been found that for these aspect ratios the CFV is inversely proportional to a resulting in surprisingly low filler volume loadings, of the order of 0.01%, required to achieve percolation in such systems. By studying fluctuations of the CFV and the density of the percolation clusters, various critical indices of the percolation theory have been calculated including the critical index of conductivity, t. For three-dimensional systems it has been found that t decreases substantially with an increase in the aspect ratio. The calculated thermal and electrical conductivity of the nanotube suspensions and composites as functions of the nanotube loading is in good agreement with recent experimental data.