Silica Supraparticles with Self‐Oscillatory Vertical Propulsion: Mechanism & Theoretical Description
Silica Supraparticles with Self‐Oscillatory Vertical Propulsion: Mechanism & Theoretical Description
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具有自振荡垂直推进力的二氧化硅超颗粒：机制
DOI：
10.1002/ppsc.202200021
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发表时间：
2022
影响因子：
2.7
通讯作者：
Gradzielski, Michael
中科院分区：
文献类型：
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作者：
Kim, Hyung‐Ju;Sperling, Marcel;Velev, Orlin D.;Gradzielski, Michael
提出了一种新型的mm尺寸的基于二氧化硅的自推进超粒子，其显示浮力驱动的均匀垂直振荡运动，使用过氧化氢（H2 O2）水溶液作为化学燃料。超微粒子是通过一个强大的液滴模板技术制备的，通过干燥胶体悬浮液滴含有二氧化硅微球和催化Fe3O4@Pt修饰的纳米粒子在超疏水Cu-Ag表面。由Pt催化的H2 O2分解产生的氧气被释放并聚集在疏水超微粒表面上。这导致浮力和颗粒上升到表面，在那里氧气泡被释放，颗粒再次下降，导致以非常规则的方式振荡过程。这一过程的机制的特点和定量分析在这里的重力和浮力的平衡。颗粒运动的理论模型描述了颗粒振荡周期如何依赖于H2 O2浓度。这种新型的自推进粒子可以在混合和催化中找到潜在的应用，特别是由于它们的周期性运动具有高度的规律性。
A novel type of mm‐sized silica‐based self‐propelling supraparticles displaying buoyancy‐driven homogeneous vertical oscillatory motion using aqueous hydrogen peroxide (H2O2) as chemical fuel is presented. The supraparticles are prepared via a robust droplet templating technique by drying colloidal suspension droplets containing silica microspheres and catalytic Fe3O4@Pt decorated nanoparticles on a superhydrophobic Cu–Ag surface. Oxygen gas originating from Pt catalyzed decomposition of H2O2is released and gathered onto the hydrophobic supraparticle surface. This causes buoyancy and uplift of the particle to the surface, where the oxygen bubble is released and the particle descents again, leading to an oscillating process in a very regular fashion. The mechanism of this process is characterized and analyzed here quantitatively by a balance of the gravitational and buoyant forces. The theoretical model of particle movement describes how the particle oscillation period depends on the H2O2concentration. This novel type of self‐propelling particles could find potential applications in mixing and catalysis, especially due to the high regularity of their periodic movement.