Reversed Janus Micro/Nanomotors with Internal Chemical Engine
| Autor: | Mihail N. Popescu, Albert Miguel-López, Samuel Sanchez, Dong-Pyo Kim, Xing Ma, Kersten Hahn, William E. Uspal, Seungwook Jang |
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| Rok vydání: | 2016 |
| Předmět: |
Materials science
Janus particles General Physics and Astronomy micromachines Nanotechnology 02 engineering and technology 010402 general chemistry 01 natural sciences Article Microtechnology General Materials Science mesoporous silica Janus Aqueous solution General Engineering Mesoporous silica 021001 nanoscience & nanotechnology self-propulsion 0104 chemical sciences Active matter micro/nanomotors Chemical species Particle phoretic motion 0210 nano-technology |
| Zdroj: | ACS Nano |
| ISSN: | 1936-086X 1936-0851 |
| Popis: | Self-motile Janus colloids are important for enabling a wide variety of microtechnology applications as well as for improving our understanding of the mechanisms of motion of artificial micro- and nanoswimmers. We present here micro/nanomotors which possess a reversed Janus structure of an internal catalytic “chemical engine”. The catalytic material (here platinum (Pt)) is embedded within the interior of the mesoporous silica (mSiO2)-based hollow particles and triggers the decomposition of H2O2 when suspended in an aqueous peroxide (H2O2) solution. The pores/gaps at the noncatalytic (Pt) hemisphere allow the exchange of chemical species in solution between the exterior and the interior of the particle. By varying the diameter of the particles, we observed size-dependent motile behavior in the form of enhanced diffusion for 500 nm particles, and self-phoretic motion, toward the nonmetallic part, for 1.5 and 3 μm ones. The direction of motion was rationalized by a theoretical model based on self-phoresis. For the 3 μm particles, a change in the morphology of the porous part is observed, which is accompanied by a change in the mechanism of propulsion via bubble nucleation and ejection as well as a change in the direction of motion. |
| Databáze: | OpenAIRE |
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