| 摘要: | 近年來微機電的發展帶動微流體操控的興起，其應用以生物、化
學試驗為主，常見微流體操控有化學驅動、靜電力、熱毛細、電濕潤
等，而熱毛細驅動具有低汙染、設備簡單、控制容易等優點，傳統熱
毛細力驅動主要以固體平台為主，利用液珠兩側因溫度差而相異的表
面張力，造成接觸角改變形成位移。，此種平台不可避免的會有溫度
梯度要求過高以及液體殘留等缺點。
本文選用與水不相溶之油體做為操控平台，主要是找尋與傳統熱
毛細力驅動截然不同的控制方式，新型液體平台則是使用馬蘭哥尼效
應所產生液體表面高低改變，間接驅動上方目標液體移動。實驗平台
選定矽油與氟化油兩種流體所組成的三種介面為主軸進行探討，在矽
油平台上滴入液滴，發現液滴因介面張力作用而漂浮於矽油表面之上，
而矽油平台冷熱端的溫度梯度使得液面傾斜驅動液珠向熱端遷移，此
速度高於相同溫度梯度的固體熱毛細驅動平台。而使用氟化油與矽油
所組成的雙層流體平台，可以讓液滴更加穩地的停留於平台介面，此
種方式依然可以利用介面傾斜來驅動液珠，但由於受到流場阻力的阻
礙，移動速度相較緩慢，最後使用史托克阻力定律估算流場產生阻力，
計算出淨力總和。最後利用流體平台的傾斜與流場特性，發現可以在
同一平台上實現讓兩種不同顆粒大小液珠進行相反方向的運動。;In recent years, the growth of microfluidic manipulation has improved
with the rapid development of microelectromechanics, and its practices are
mainly applied to biological and chemical experiments. Common
microfluidic manipulations include chemical drive, electrostatic force,
thermocapillary, and electrowetting. In particular, thermocapillary drive has
several advantages such as low pollution, simple operation, and easy to
control. The traditional thermocapillary force is driven mainly based on a
solid platform, which uses the different surface tension on both sides of the
liquid drop due to the temperature difference, causing the contact angle to
change to form a displacement. Nevertheless, the design of this platform
inevitably have disadvantages such as high temperature gradient and liquid
residue.
In this article, the oil that is incompatible with water is used as the
control platform. The main purpose is to find a control method that is
completely different from the traditional thermocapillary force drive. The
new liquid platform uses the Marangoni effect to produce the liquid surface
level change to indirectly make the top liquid target move. The experimental
platform selects three interfaces which are composed of two fluids of
silicone oil and fluorinated oil as the main axis for discussion. Then
Droplets are dropped on the silicone oil platform, and it is found that the
droplets float on the surface of the silicone oil due to the interface tension.
The temperature gradient makes the liquid surface tilt to drive the liquid
iv
beads to migrate to the hot end, which is higher than the solid
thermocapillary drive platform with the same temperature gradient. The use
of a two-layer fluid platform composed of fluorinated oil and silicone oil
can make the droplets stay on the platform interface more stably. This
method can still use the tilt of the interface to drive the droplets, but due to
the resistance of the flow field, The moving speed is relatively slow, and
finally the resistance produced by the flow field is estimated using Stoke′s
law of resistance, and the total net force is calculated. Finally, using the tilt
and flow field characteristics of the fluid platform, it is found that two liquid
beads of different particle sizes can be moved in opposite directions on the
same platform. |
