Institute for Molecules and Materials, Radboud University, 6525 AJ, Nijmegen, The Netherlands.
Soft Condensed Matter, Debye Institute for Nanomaterials Science, Utrecht University, 3584 CH, The Netherlands.
Soft Matter. 2016 Dec 6;12(48):9657-9665. doi: 10.1039/c6sm01760f.
In recent years, there is a growing interest in designing artificial analogues of living systems, fueled not only by potential applications as 'smart micro-machines', but also by the demand for simple models that can be used to study the behavior of their more complex natural counterparts. Here, we present a facile, internally driven, experimental system comprised of fluorescently labeled colloidal silica rods of which the self-propulsion is powered by the decomposition of HO catalyzed by a length-wise half Pt coating of the particles in order to study how shape anisotropy and swimming direction affect the collective behavior. We investigated the emerging structures and their time evolution for various particle concentrations in (quasi-)two dimensional systems for three aspect ratios of the rods on a single particle level using a combination of experiments and simulations. We found that the dynamic self-organization relied on a competition between self-propulsion and phoretic attractions induced by phoresis of the rods. We observed that the particle clustering behavior depends on the concentration as well as the aspect ratio of the rods. Our findings provide a more detailed understanding of dynamic self-organization of anisotropic particles and the role the propulsion direction plays in internally driven systems.
近年来，人们对设计模仿生命系统的人工系统越来越感兴趣，这不仅是因为它们作为“智能微型机器”的潜在应用，还因为人们需要简单的模型来研究其更复杂的天然对应物的行为。在这里，我们提出了一种简单的、内部驱动的实验系统，该系统由荧光标记的胶体二氧化硅棒组成，其自推进是由 HO 的分解驱动的，HO 的分解由颗粒的纵向一半 Pt 涂层催化，以便研究形状各向异性和游动方向如何影响集体行为。我们在（准）二维系统中针对三种棒的纵横比在单个颗粒水平上研究了不同颗粒浓度的新兴结构及其随时间的演化，使用了实验和模拟的组合。我们发现，动态自组织依赖于自推进和由棒的流动引起的趋药性吸引力之间的竞争。我们观察到，颗粒的聚类行为不仅取决于浓度，还取决于棒的纵横比。我们的发现提供了对各向异性颗粒的动态自组织以及内部驱动系统中推进方向所起作用的更详细的理解。
