Nanoparticle Diffusion in Polymer Nanocomposites
Nanoparticle Diffusion in Polymer Nanocomposites
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DOI：
10.1103/physrevlett.112.108301
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发表时间：
2014-03-12
影响因子：
8.6
通讯作者：
Kumar, Sanat K.
中科院分区：
文献类型：
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作者：
Kalathi, Jagannathan T.;Yamamoto, Umi;Kumar, Sanat K.
大规模的分子动力学模拟表明，纳米粒子（NP）的扩散系数在弱相互作用的混合物的NP和聚合物熔体有两个非常不同的类的行为取决于它们的大小。NP弛豫时间和它们的扩散率完全描述的本地，劳斯动力学的聚合物链的NP小于聚合物缠结网格尺寸。与纠缠网格尺寸相当的较大NP的运动被链纠缠显着减慢，并且不能通过斯托克斯-爱因斯坦关系描述。我们的研究结果基本上是定量协议与力水平的广义朗之万方程理论的所有NP大小和链长的探索，并意味着，对于这些轻纠缠系统，激活NP跳跃是不重要的。
Large-scale molecular dynamics simulations show that nanoparticle (NP) diffusivity in weakly interacting mixtures of NPs and polymer melts has two very different classes of behavior depending on their size. NP relaxation times and their diffusivities are completely described by the local, Rouse dynamics of the polymer chains for NPs smaller than the polymer entanglement mesh size. The motion of larger NPs, which are comparable to the entanglement mesh size, is significantly slowed by chain entanglements, and is not describable by the Stokes-Einstein relationship. Our results are in essentially quantitative agreement with a force-level generalized Langevin equation theory for all the NP sizes and chain lengths explored, and imply that for these lightly entangled systems, activated NP hopping is not important.