Studies on Marangoni vortex flows generated by photothermal effect of nano-structured thin films

2016 Fiscal Year Final Research Report

• Project/Area Number: 15H06310
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Single-year Grants
• Research Field: Nano/Microsystems
• Research Institution: Kyoto University
• Principal Investigator: Namura Kyoko 京都大学, 工学研究科, 助教 (20756803)
• Project Period (FY): 2015-08-28 – 2017-03-31
• Keywords: マランゴニ対流 / マイクロバブル / 金ナノ粒子 / 光熱変換 / 熱プラズモニック効果 / マイクロ流体

Outline of Final Research Achievements

In this study, manipulation and mixing of small amount of water has been demonstrated by using surface tension of a tiny bubble. By focusing a laser onto a nanostructured thin film, the local temperature of water on the laser spot rises and a bubble is generated. The localized heat generation disproportions the surface tension of the bubble and induces flow around it. By tuning the laser spot position and power, the flow has been controlled to demonstrate particles focusing and flow direction switching in a small fluidic cell. In addition, by eliminating dissolved gasses in water, we successfully demonstrated generation of a tiny water vapor microbubble in the water. The water vapor microbubble involves rapid flow with flow speed of more than 1 m/s. Because the water vapor bubble exists only during the local heating of the water, it is useful as a micro-mixer that is producible and removable in any places and any time in the micrometer-size channel.

Free Research Field

ナノ構造薄膜，光熱変換