Tsuji Tetsuro, Iseki Hirotaka, Hanasaki Itsuo, Kawano Satoyuki
Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
J Phys Condens Matter. 2017 Nov 29;29(47):475101. doi: 10.1088/1361-648X/aa9350.
Thermophoretic forces acting on nanoparticles are investigated using molecular dynamics simulation. We assume the Lennard-Jones (LJ) potential for the interaction between fluid molecules. On the other hand, the interaction between the nanoparticle and the surrounding fluid molecules are assumed to be either LJ or Weeks-Chandler-Andersen (WCA) potential, where the latter is purely-repulsive. The effect of the interaction potential on the thermophoretic force is investigated for various situations. It is found that the thermophoretic force basically acts in the direction from the hotter side to the colder side of the nanoparticle. However, when the surrounding fluid is in the liquid phase, the force acts in the reversed direction for the case of the WCA potential. It is clarified that the sign reversal is caused by the different structures observed in the distribution of repulsive forces acting on the nanoparticle.
利用分子动力学模拟研究了作用于纳米颗粒的热泳力。我们假设流体分子之间的相互作用采用 Lennard-Jones（LJ）势。另一方面，纳米颗粒与周围流体分子之间的相互作用假定为 LJ 势或 Weeks-Chandler-Andersen（WCA）势，其中后者是纯排斥势。针对各种情况研究了相互作用势对热泳力的影响。结果发现，热泳力基本上沿纳米颗粒从较热一侧指向较冷一侧的方向起作用。然而，当周围流体处于液相时，对于 WCA 势的情况，力的作用方向相反。结果表明，符号反转是由作用于纳米颗粒的排斥力分布中观察到的不同结构引起的。
