Wang Zhengjia, Chu Kang-Ching, Tsao Heng-Kwong, Sheng Yu-Jane
Condensed Matter Science and Technology Institute, School of Instrumentation Science and Engineering, Harbin Institute of Technology, Harbin 150080, People's Republic of China.
Phys Chem Chem Phys. 2021 Aug 4;23(30):16234-16241. doi: 10.1039/d1cp01065d.
In a channel connected to a reservoir, passive particles prefer staying in the reservoir than the channel due to the entropic effect, as the size of the particles is comparable to that of the channel. Self-propelled rods can exhibit out-of-equilibrium phenomena, and their partition behavior may differ from that of passive rods due to their persistent swimming ability. In this work, the distribution of active nano-rods between the nanoscale channel and reservoir is explored using dissipative particle dynamics. The ratio of the nano-rod concentration in the slit to that in the reservoir, defined as the partition ratio Ψ, is a function of active force, channel width, and rod length. Although passive nano-rods prefer staying in bulk (Ψ < 1), active rods can overcome the entropic barrier and show favorable partition toward narrow channels (Ψ > 1). As the slit width decreases to about the rod's width, active rods entering the slit behave like a quasi-two-dimensional system dynamically. At sufficiently high concentrations and Peclet numbers, nano-rods tend to align and move together in the same direction for a certain time. The distribution (PM) of the cluster size (M) follows a power law, PM ∝ M-2, for small clusters.
在连接到储液器的通道中，由于熵效应，当颗粒尺寸与通道尺寸相当时，被动颗粒更倾向于留在储液器中而非通道内。自推进杆可表现出非平衡现象，且由于其持续的游动能力，它们的分配行为可能与被动杆不同。在这项工作中，使用耗散粒子动力学研究了活性纳米杆在纳米级通道和储液器之间的分布。狭缝中纳米杆浓度与储液器中纳米杆浓度之比，定义为分配比Ψ，是活性力、通道宽度和杆长度的函数。尽管被动纳米杆更倾向于留在主体中（Ψ<1），但活性杆可以克服熵垒并表现出对狭窄通道的有利分配（Ψ>1）。当狭缝宽度减小到约杆的宽度时，进入狭缝的活性杆在动力学上表现得像一个准二维系统。在足够高的浓度和佩克莱数下，纳米杆倾向于在一段时间内沿同一方向排列并一起移动。对于小簇，簇尺寸（M）的分布（PM）遵循幂律，PM∝M-2。
