Molecular simulation of the diffusion mechanism of nanorods in cross-linked networks.
Molecular simulation of the diffusion mechanism of nanorods in cross-linked networks.
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DOI：
10.1039/d1nr05368j
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发表时间：
2021-10
期刊：
影响因子：
6.7
通讯作者：
Bo-Ran Zhao;Bin Li;Xinghua Shi
中科院分区：
文献类型：
--
作者：
Bo-Ran Zhao;Bin Li;Xinghua Shi
我们用粗粒度分子动力学(CGMD)模拟研究了不同刚性和长径比的棒状纳米载流子在交联网络中的扩散。纳米棒的扩散率随着纳米棒和网络的刚性的降低而增加，以及随着相对于相同体积分数的纳米棒的长径比的增加而增加。纳米棒在短时间尺度上沿其主轴移动呈现出各向异性的扩散路径，在长时间尺度上扩散的各向异性减小。同时，纳米棒的扩散在大多数情况下表现出偏离布朗运动的次扩散机制，这是由于纳米棒被捕获在由网络组成的笼子中。当纳米棒从笼子中逃脱时，它可以跳跃，跳跃行为取决于纳米棒和网络的刚性以及局部网络密度。被捕获的纳米棒的旋转运动也增加了跳跃的概率。我们的结果可能有助于理解棒状和其他相关纳米载体在交联网络环境中扩散的微观机制。
We study the diffusion of rod-shaped nanocarriers with different rigidities and aspect ratios in cross-linked networks using coarse-grained molecular dynamics (CGMD) simulations. The diffusivity of the nanorods increases with a reduction in the rigidities of the nanorods and network, as well as with an increasing aspect ratio with respect to the same volume fraction of the nanorods. The nanorods show an anisotropic diffusion pathway through translocating along their major axes at short time scales, and the anisotropy of diffusion decreases at long time scales. Meanwhile, the diffusion of the nanorods shows a sub-diffusion regime that deviates from Brownian motion in most cases due to the trapping of the nanorods in a cage composed of the network. The nanorod could hop when it escapes from the cage and the hopping behavior depends on the rigidities of both the nanorod and network, as well as the local network density. The rotational motion of the trapped nanorod also enhances the probability of hopping. Our results may help in the understanding of the microscopic mechanism for the diffusion of rod-shaped and other relevant nanocarriers, in a cross-linked network environment.