Soft Condensed Matter, Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands.
J Chem Phys. 2017 Aug 28;147(8):084902. doi: 10.1063/1.4989764.
We study a three-dimensional system of self-propelled Brownian particles interacting via the Lennard-Jones potential. Using Brownian dynamics simulations in an elongated simulation box, we investigate the steady states of vapour-liquid phase coexistence of active Lennard-Jones particles with planar interfaces. We measure the normal and tangential components of the pressure tensor along the direction perpendicular to the interface and verify mechanical equilibrium of the two coexisting phases. In addition, we determine the non-equilibrium interfacial tension by integrating the difference of the normal and tangential components of the pressure tensor and show that the surface tension as a function of strength of particle attractions is well fitted by simple power laws. Finally, we measure the interfacial stiffness using capillary wave theory and the equipartition theorem and find a simple linear relation between surface tension and interfacial stiffness with a proportionality constant characterized by an effective temperature.
我们研究了一个由通过 Lennard-Jones 势相互作用的自主布朗粒子组成的三维系统。通过在长形模拟盒中的布朗动力学模拟，我们研究了具有平面界面的活性 Lennard-Jones 粒子的汽液相共存的稳定状态。我们测量了垂直于界面方向的压力张量的法向和切向分量，并验证了两个共存相的力学平衡。此外，我们通过整合压力张量的法向和切向分量的差异来确定非平衡界面张力，并表明表面张力作为粒子吸引力强度的函数很好地符合简单的幂律。最后，我们使用毛细波理论和等分配定理测量界面刚度，并发现表面张力和界面刚度之间存在简单的线性关系，比例常数由有效温度来表征。
