Araki Takeaki, Fukai Shintaro
Department of Physics, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.
Soft Matter. 2015 May 7;11(17):3470-9. doi: 10.1039/c4sm02357a.
We numerically investigate the propelled motions of a Janus particle in a periodically phase-separating binary fluid mixture. In this study, the surface of the particle tail prefers one of the binary fluid components and the particle head is neutral in the wettability. During the demixing period, the more wettable phase is selectively adsorbed to the particle tail. Growths of the adsorbed domains induce the hydrodynamic flow in the vicinity of the particle tail, and this asymmetric pumping flow drives the particle toward the particle head. During the mixing period, the particle motion almost ceases because the mixing primarily occurs via diffusion and the resulting hydrodynamic flow is negligibly small. Repeating this cycle unboundedly moves the Janus particle toward the head. The dependencies of the composition and the repeat frequency on the particle motion are discussed.
我们对周期性相分离二元流体混合物中雅努斯粒子的推进运动进行了数值研究。在本研究中，粒子尾部表面更倾向于二元流体中的一种组分，而粒子头部的润湿性是中性的。在相分离期间，润湿性更强的相被选择性地吸附到粒子尾部。吸附域的生长在粒子尾部附近诱导了流体动力流，这种不对称的抽吸流将粒子朝着粒子头部驱动。在混合期间，粒子运动几乎停止，因为混合主要通过扩散发生，并且由此产生的流体动力流小到可以忽略不计。无限重复这个循环会使雅努斯粒子朝着头部移动。讨论了组成和重复频率对粒子运动的依赖性。
