A gold-capped Janus particle suspended in a near-critical binary liquid mixture can self-propel under illumination. We have immobilized such a particle in a narrow channel and studied the nonequilibrium dynamics of a binary solvent around it, using experiment and numerical simulations. For the latter we consider both a purely diffusive and a hydrodynamic model. All approaches indicate that the early time dynamics is purely diffusive and characterized by composition layers traveling with a constant speed from the surface of the colloid into the bulk. Subsequently, hydrodynamic effects set in and the transient state is destroyed by strong nonequilibrium concentration fluctuations, which arise as a result of the temperature gradient and the vicinity of the critical point of the binary liquid mixture. They give rise to a complex, permanently changing coarsening patterns. For a mobile particle, the transient dynamics results in propulsion in the direction opposite to that observed after the steady state is attained.
Dynamics of Motility-Induced clusters: coarsening beyond Ostwald ripening
我们研究集群的动力学的主动布朗运动诱导相分离产生的，通过应用我们设计的算法来跟踪集群轨迹。我们确定了一个聚集机制，超越奥斯特瓦尔德熟化，但也产生$z=3$。质量$M$自推进的活性团簇具有增强的扩散性$D\sim$ Pe $^2/\sqrt{M}$。它们的快速运动驱动聚集成大的分形结构，这些结构是不同的六角序的拼凑，并与规则的、取向均匀的较小结构共存。为了显示活动的影响，我们对一个被动系统进行了比较研究，该系统与主动系统存在重大差异。
Active motility and wetting cooperatively regulate liquid-liquid phase separation
Advanced Materials Thrust, Function Hub, The Hong Kong University of Science and Technology (Guangzhou)（香港科技大学（广州）功能枢纽先进材料 thrust）；Institute of Chinese Medical Sciences & State Key Laboratory of Mechanism and Quality of Chinese Medicine, University of Macau（澳门大学中医药学院及中药质量研究国家重点实验室）；Department of Pharmaceutical Sciences, Faculty of Health Sciences, University of Macau（澳门大学健康科学学院药学系）；Zhuhai UM Science and Technology Research Institute, University of Macau（澳门大学珠海科学技术研究院）；Research Center for Advanced Science and Technology, The University of Tokyo（东京大学先进科学技术研究中心）；Department of Fundamental Engineering, Institute of Industrial Science, The University of Tokyo（东京大学工业科学研究所基础工程系）
Self-Organized Critical Coexistence Phase in Repulsive Active Particles
我们重新运动诱导相分离的两个模型的活性粒子相互作用的成对排斥。我们表明，由此产生的致密相包含气泡代数分布到一个典型的大截止尺度。在足够大的系统尺寸和/或全局密度下，所有气体可以包含在气泡内，此时系统以有限的截止气泡尺度进行微相分离。我们观察到的顺序是异常的，具有不同的动力学的致密相和气泡的粗化。这种现象通过“简化气泡模型”再现，该模型实现了Tjhung等人提出的反向奥斯特瓦尔德成熟的基本思想[Phys. Rev. X 8，031080（2018）]。
