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Evaporation Induced Spontaneous Micro-Vortexes through Engineering of the Marangoni Flow |
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| Authors: | Zheren Cai Dr. Zhandong Huang Dr. Zheng Li Dr. Meng Su Zhipeng Zhao Dr. Feifei Qin Zeying Zhang Prof. Jun Yang Prof. Yanlin Song |
| Affiliation: | 1. Key Laboratory of Green Printing, Institute of Chemistry, Chinese Academy of Sciences (ICCAS), Beijing Engineering Research Center of Nanomaterials for Green Printing Technology, National Laboratory for Molecular Sciences (BNLMS), Beijing, 100190 P. R. China;2. Department of Mechanical and Materials Engineering, The University of Western Ontario, London, Ontario, N6A 5B9 Canada;3. Key Laboratory of Green Printing, Institute of Chemistry, Chinese Academy of Sciences (ICCAS), Beijing Engineering Research Center of Nanomaterials for Green Printing Technology, National Laboratory for Molecular Sciences (BNLMS), Beijing, 100190 P. R. China University of Chinese Academy of Sciences, Beijing, 100049 P. R. China;4. Chair of Building Physics, Department of Mechanical and Process Engineering, ETH Zürich (Swiss Federal Institute of Technology in Zürich), Zürich, 8092 Switzerland |
| Abstract: | Vortex flow fields are widely used to manipulate objects at the microscale in microfluidics. Previous approaches to produce the vortex flow field mainly focused on inertia flows. It remains a challenge to create vortexes in Stokes flow regime. Here we reported an evaporation induced spontaneous vortex flow system in Stokes flow regime by engineering Marangoni flow in a micro-structured microfluidic chip. The Marangoni flow is created by nonuniform evaporation of surfactant solution. Various vortexes are constructed by folding the air–water interface via microstructures. Patterns of vortexes are programmable by designing the geometry of the microstructures and are predictable using numerical simulations. Moreover, rotation of micro-objects and enrichment of micro-particles using vortex flow is demonstrated. This approach to create vortexes will provide a promising platform for various microfluidic applications such as biological analysis, chemical synthesis, and nanomaterial assembly. |
| Keywords: | Marangoni flow microfluidics particle manipulation Stokes flow vortex |