Max Planck Institute for Colloids and Interfaces, Department of Interfaces, D14476, Germany.
Small. 2014 Jul 9;10(13):2670-7. doi: 10.1002/smll.201303571. Epub 2014 Mar 24.
Bubbles are widely used by animals in nature in order to fulfill important functions. They are used by animals in order to walk underwater or to stabilize themselves at the water/air interface. The main aim of this work is to imitate such phenomena, which is the essence of biomimetics. Here, bubbles are used to propel and to control the location of Janus particles in an aqueous medium. The synthesis of Janus SiO2-Ag and polystyrene-Ag (PS-Ag) particles through embedment in Parafilm is presented. The Janus particles, partially covered with catalytically active Ag nanoparticles, are redispersed in water and placed on a glass substrate. The active Ag sites are used for the splitting of H2O2 into water and oxygen. As a result, an oxygen bubble is formed on one side of the particle and promotes its propulsion. Once formed, the bubble-particle complex is stable and therefore, can be manipulated by tuning hydrophilic-hydrophobic interactions with the surface. In this way a transition between two- and three- dimensional motion is possible by changing the hydrophobicity of the substrate. Similar principles are used in nature.
气泡在自然界中被广泛应用于动物，以满足重要的功能。它们被用于在水下行走或在水/气界面上保持稳定。这项工作的主要目的是模仿这些现象，这就是仿生学的本质。在这里，气泡用于推动和控制 Janus 颗粒在水介质中的位置。通过嵌入 Parafilm 合成了 Janus SiO2-Ag 和聚苯乙烯-银（PS-Ag）颗粒。部分覆盖有催化活性 Ag 纳米颗粒的 Janus 颗粒在水中重新分散，并放置在玻璃基板上。活性 Ag 位用于将 H2O2 分解为水和氧气。结果，在颗粒的一侧形成氧气气泡并促进其推进。一旦形成，气泡-颗粒复合物是稳定的，因此可以通过调节与表面的亲水性-疏水性相互作用来进行操纵。通过改变基底的疏水性，可以实现从二维到三维运动的转变。类似的原理在自然界中也有应用。
