Aggregation and segregation of confined active particles.
Aggregation and segregation of confined active particles.
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DOI：
10.1039/c4sm00927d
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发表时间：
2014-03
期刊：
影响因子：
3.4
通讯作者：
Xingbo Yang;M. Manning;M. Marchetti
中科院分区：
文献类型：
--
作者：
Xingbo Yang;M. Manning;M. Marchetti
我们模拟了一个模型的自推进磁盘与软排斥相互作用局限于一个盒子在两个维度。对于小的旋转扩散速率，单分散盘自发地积聚在壁上。在低密度下，粒子之间的相互作用力是强烈不均匀的，一个简单的模型预测了这些不均匀性如何改变状态方程。在更高的密度下，集体效应变得重要。我们观察到的干扰过渡的包装分数为0.88，这也是非活性无热单分散磁盘的干扰点的签名。在此期间，系统产生壁聚集所需的临界有限主动速度。当填充分数高于0.6时，压力随着密度的增加而降低，这表明粒子之间的强相互作用正在影响远低于堵塞转变的状态方程。在没有任何粘附的情况下，双分散盘的混合物分离，确定了一种新的机制，可能有助于胚胎发育中的细胞分选。
We simulate a model of self-propelled disks with soft repulsive interactions confined to a box in two dimensions. For small rotational diffusion rates, monodisperse disks spontaneously accumulate at the walls. At low densities, interaction forces between particles are strongly inhomogeneous, and a simple model predicts how these inhomogeneities alter the equation of state. At higher densities, collective effects become important. We observe signatures of a jamming transition at a packing fraction ϕ ∼ 0.88, which is also the jamming point for non-active athermal monodisperse disks. At this ϕ, the system develops a critical finite active speed necessary for wall aggregation. At packing fractions above ϕ ∼ 0.6, the pressure decreases with increasing density, suggesting that strong interactions between particles are affecting the equation of state well below the jamming transition. A mixture of bidisperse disks segregates in the absence of any adhesion, identifying a new mechanism that could contribute to cell sorting in embryonic development.