论文标题
具有可逆相互作用的活动粒子的轻切口推进
Light-switchable propulsion of active particles with reversible interactions
论文作者
论文摘要
诸如微生物和自propelled颗粒之类的活性系统显示出众多的集体现象，包括蜂群，聚类和相位分离。控制各个自行旋转单元之间相互作用的推进方向和切换性可能会在设计内部设计材料时开放新的途径。在这里，我们提出了一个自构的粒子系统，该系统由半金涂层的二氧化钛（$ \ mathrm {tio} _2 $）粒子组成，在该粒子中，我们可以通过利用两侧的不同光催化活性来快速而按需扭转推进方向。我们证明，推进方向的逆转将流体动力相互作用的性质从吸引力到排斥性，并且可以驱动粒子组件进行融合和裂变过渡。此外，我们表明这些活性胶体可以充当成核位点，并迅速切换活性和被动颗粒之间的相互作用，从而导致可重构组装和拆卸。我们的实验是通过最小的流体动力模型定性描述的。
Active systems such as microorganisms and self-propelled particles show a plethora of collective phenomena, including swarming, clustering, and phase separation. Control over the propulsion direction and switchability of the interactions between the individual self-propelled units may open new avenues in designing of materials from within. Here, we present a self-propelled particle system, consisting of half-gold coated titania ($\mathrm{TiO}_2$) particles, in which we can fast and on-demand reverse the propulsion direction, by exploiting the different photocatalytic activities on both sides. We demonstrate that the reversal in propulsion direction changes the nature of the hydrodynamic interaction from attractive to repulsive and can drive the particle assemblies to undergo both fusion and fission transitions. Moreover, we show these active colloids can act as nucleation sites, and switch rapidly the interactions between active and passive particles, leading to reconfigurable assembly and disassembly. Our experiments are qualitatively described by a minimal hydrodynamic model.
