0

Full Content is available to subscribers

Subscribe/Learn More  >

Noncontact Bubble Manipulation in Microchannel by Using Photothermal Marangoni Effect

[+] Author Affiliations
Hiroyuki Takeuchi, Masahiro Motosuke, Shinji Honami

Tokyo University of Science, Tokyo, Japan

Paper No. ICNMM2009-82159, pp. 1023-1030; 8 pages
doi:10.1115/ICNMM2009-82159
From:
  • ASME 2009 7th International Conference on Nanochannels, Microchannels, and Minichannels
  • ASME 2009 7th International Conference on Nanochannels, Microchannels and Minichannels
  • Pohang, South Korea, June 22–24, 2009
  • Conference Sponsors: Nanotechnology Institute
  • ISBN: 978-0-7918-4349-9 | eISBN: 978-0-7918-3850-1
  • Copyright © 2009 by ASME

abstract

A novel method of noncontact bubble manipulation by optically-induced local surface tension gradient is described in this paper. In microfluidic devices, the effects of interfacial phenomena become dominant with decreasing of a length scale. An unexpected adhesion of a bubble on the channel wall is a serious problem which can cause the large pressure loss and the deterioration of the device. Thus, the removal or manipulation technique of the bubble is strongly required. In this study we controlled the thermocapillary force around the bubble by means of optical technique. The purpose of this study is the verification of the optical manipulation method of bubble. Particularly, the detail of migration process including the effect of bubble size, fluid viscosity and optical power is discussed. The manipulation experiments were conducted for the bubble with the diameter of 40 to 140 μm in a microchannel filled with silicone oil. An FEP (fluorinated ethylene propylene copolymer) tube with the inner diameter of 200 μm was used as the microchannel. The optical system for the heating is composed of a scanning setup and a compact laser diode. In this technique, two types of motion for the bubble transport are possible. One motion is the detachment of the bubble from the channel wall. When a laser beam is irradiated into the liquid in the vicinity of the bubble attached to the wall, the Marangoni convection is induced and the difference of pressure is generated around the bubble. The bubble is detached from the wall when the pressure difference overcomes the anchoring force between the bubble and the wall. Then, the bubble detached from the wall is suspended in the liquid at the balanced position between the thermocapillary and buoyancy force. This position can be controlled by adjusting the laser power. The other motion is the manipulation of the bubble along the channel. When the focal spot is scanned along the channel, it is possible to manipulate the bubble as if the bubble follows the light. In addition, the minimum optical power necessary to transport the bubble along the microchannel was measured. The minimum optical power strongly depends on bubble size, liquid viscosity, and scanning speed. These results show the relationship between the driving force induced by photothermal Marangoni effect and the resistance force related with the viscosity and the scanning speed.

Copyright © 2009 by ASME

Figures

Tables

Interactive Graphics

Video

Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature

Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In