Noncontact Bubble Manipulation in Microchannel by Using Photothermal Marangoni Effect
Noncontact Bubble Manipulation in Microchannel by Using Photothermal Marangoni Effect
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DOI：
10.1080/01457632.2011.562753
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发表时间：
2012-02
影响因子：
2.3
通讯作者：
H. Takeuchi;M. Motosuke;S. Honami
中科院分区：
文献类型：
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作者：
H. Takeuchi;M. Motosuke;S. Honami
本文描述了一种利用光致局部表面张力梯度对气泡进行非接触操纵的方法。在微流控器件中，随着长度尺度的减小，界面现象的影响逐渐占主导地位。适当控制界面性质的局部梯度可以为微流体系统中的气泡处理提供有力的方法。在这里，光热技术被用来诱导微泡周围的表面张力梯度。气泡周围的热毛细力是由局部激光聚焦引起和控制的。为了验证基于光热Marangoni效应的气泡光学操纵方法，对填充不同粘度硅油的微通道中的气泡进行了实验研究。结果表明，利用光热Marangoni效应操纵气泡有三种应用：从通道壁分离、液相捕获和通道内输运。此外，还评价了操作的最小光焦度。气泡尺寸、液体粘度和照射光功率对操纵特性的影响可以由无量纲数来概括，该无量纲数是气泡的热毛细力与粘性拖曳力的比率。
A noncontact bubble manipulation by an optically induced local surface tension gradient is described in this paper. In microfluidic devices, the effects of interfacial phenomena become dominant with decreasing of the length scale. An appropriate control of the local gradient of the interfacial properties can provide a powerful method for bubble handling in the microfluidic system. Here, the photothermal technique is used to induce the gradient in surface tension around a microbubble. The thermocapillary force around the bubble is induced and controlled by local laser focusing. The bubble in a microchannel filled with silicone oil with varied viscosity was examined to verify experimentally the optical manipulation method of bubbles based on the photothermal Marangoni effect. As a result, three applications of bubble manipulation by using photothermal Marangoni effect are obtained: detachment from channel wall, trapping in liquid phase, and transportation in the channel. Additionally, minimum optical power for the manipulation was evaluated. The effects of bubble size, liquid viscosity, and irradiated optical power on the manipulation characteristics can be summarized by a dimensionless number that is a ratio of the thermocapillary force to viscous drag force for the bubble.