Department of Chemical Physics & Hefei National Laboratory for Physical Sciences at Microscales, iChEM, University of Science and Technology of China, Hefei, Anhui 230026, China.
Soft Matter. 2017 Jun 7;13(22):4112-4121. doi: 10.1039/c7sm00519a.
Recent studies showed substantial evidence of dynamic clustering and phase separation in active particle systems, but the role of anisotropic interaction between the particles has not been addressed yet. Here we investigate the phase separation of active particles that experience an anisotropic Janus interaction with tunable strength in two dimensional space by using Langevin dynamics simulations. Interestingly, we find that phase separation shows a re-entrance behavior with variation of the Janus interaction strength: while small Janus interaction can enhance the formation of living clusters and phase separation, large Janus interaction would destroy the large cluster. We explain this nontrivial phenomenon via the competition between the self-propulsion and the short-ranged Janus interaction: while self-propulsion can lead to clustering of the active particles, the Janus interaction favors the formation of states with attractive sides close to each other and repulsive sides staying apart.
最近的研究表明，在活性粒子系统中存在大量的动态聚类和相分离的证据，但粒子之间各向异性相互作用的作用尚未得到解决。在这里，我们通过使用朗之万动力学模拟研究了在二维空间中具有可调强度的各向异性雅努斯相互作用的活性粒子的相分离。有趣的是，我们发现随着雅努斯相互作用强度的变化，相分离表现出再进入行为：虽然小的雅努斯相互作用可以增强活的聚集体和相分离的形成，但大的雅努斯相互作用会破坏大聚集体。我们通过自推进和短程雅努斯相互作用之间的竞争来解释这一非平凡现象：虽然自推进可以导致活性粒子的聚集，但雅努斯相互作用有利于形成彼此吸引力大的状态，而排斥力小的状态则彼此分离。
