在微流道系統中，無須施加外力就可以操縱液滴是很想達到且重要 的目標，儘管在表面形成潤濕性梯度已經達成了這個目標，但在運輸 的距離上還是很有限，從而限制了在長距離運輸上的發展。因此我們 提出了可以透過添加三矽甲烷表面活性劑和創建深槽來達到液滴在 表面上的遠距離運輸，前者提供了 Marangoni 應力來驅動液滴移動並 同時減少接觸線遲滯，後者則引導充滿表面活性劑的液滴在有各種幾 何圖案的路徑上移動，這種液滴體積僅微升就能移動長達 20 公分以 上的距離。透過會自發性移動的液滴我們發展出一種方便且不需添加 外力的運輸液滴的方式且多種基材和液體都可適用。此外藉由從不同 分支聚集但裝載不同液體貨物的自發性移動液滴，新型態的微形反應 器也被設計出來。;Manipulating droplet transportation without inputting work is desired and important in microfluidic systems. Although the creation of wettability gradient on surfaces has been employed to achieve this goal, the transport distance is very limited, hindering its applications in long-term operations. Here, we show that programming long-ranged transport of droplets on surfaces can be achieved by the addition of trisiloxane surfactants and creation of deep grooves. The former provides Marangoni stress to actuate the droplet motion and also reduces the inherent contact line pinning. The latter acts as a railing to guide the motion of surfactant-laden droplets to follow various layouts with geometric features of roads. The droplets with microliters can move over 20 cm. This work-free method is applicable to a variety of substrate materials and liquids. By using self-running shuttles, a convenient platform for liquid cargos transport is developed and demonstrated. Moreover, coalescence of cargos carried by different shuttles is accomplished in a three-branch layout, revealing new droplet microreactors.
