Ghosh Pulak Kumar, Marchesoni Fabio, Li Yunyun, Nori Franco
Department of Chemistry, Presidency University, 86/1 College Street, Kolkata 700073, India.
Center for Phononics and Thermal Energy Science, School of Physics Science and Engineering, Tongji University, Shanghai 200092, People's Republic of China.
Phys Chem Chem Phys. 2021 May 26;23(20):11944-11953. doi: 10.1039/d1cp01088c.
Undesired advection effects are unavoidable in most nano-technological applications involving active matter. However, it is conceivable to govern the transport of active particles at the small scales by suitably tuning the relevant advection and self-propulsion parameters. To this purpose, we numerically investigated the Brownian motion of active Janus particles in a linear array of planar counter-rotating convection rolls at high Péclet numbers. Similarly to passive particles, active microswimmers exhibit advection enhanced diffusion, but only for self-propulsion speeds up to a critical value. The diffusion of faster Janus particles is governed by advection along the array's edges, whereby distinct diffusion regimes are observed and characterized. Contrary to passive particles, the relevant spatial distributions of active Janus particles are inhomogeneous. These peculiar properties of active matter are related to the combined action of noise and self-propulsion in a confined geometry and hold regardless of the actual flow boundary conditions.
在大多数涉及活性物质的纳米技术应用中，不期望的平流效应是不可避免的。然而，通过适当调整相关的平流和自推进参数，可以在小尺度上控制活性粒子的传输。为此，我们在高佩克莱数下对平面反向旋转对流卷的线性阵列中活性Janus粒子的布朗运动进行了数值研究。与被动粒子类似，活性微游动器表现出平流增强扩散，但仅适用于自推进速度达到临界值之前。速度更快的Janus粒子的扩散由沿阵列边缘的平流控制，由此观察到并表征了不同的扩散模式。与被动粒子相反，活性Janus粒子的相关空间分布是不均匀的。活性物质的这些特殊性质与受限几何结构中噪声和自推进的联合作用有关，并且与实际的流动边界条件无关。
