2013-08-012024-05-15https://scholars.lib.ntu.edu.tw/handle/123456789/664800摘要：液滴間的碰撞現象是眾多科學及技術層面的重要考量，此液面間的交互作用在近來蓬勃發展的微奈米流體之應用，也因為表面張力效應的凸顯而扮演極重要角色。本計畫分為兩部份，一為探討雙液滴於氣相介質中碰撞的基礎行為，特別是引入表面添加劑的效應，在此領域為創新研究，期能藉此更明瞭並操控異質界面間的結合現象，即可直接或間接應用於相關領域，例如微奈米機構內的流體操作與生醫檢測技術的應用，此為第二部份的主旨。我們承續先前於液滴動力學的研究，期能獲得足夠時間作一更深入的探究與發展，無論在實驗及數理分析。特別的，加入界面活性劑，我們初步發現，不只因為表面張力的改變，由於某些界面物理結構的轉變如界面活性劑的非均勻分布，產生局部應力，進而改變碰撞的特徵結果，可因此用來控制液面間的交互作用，並發展相關前瞻技術，應用於兩相微流體的操控，尤其是當液滴或氣泡在複雜幾何形狀的微流道移動，卻受制於彎管或驟縮/張而減慢。<br> Abstract: The collision dynamics between two droplets plays a crucial role in many disciplines of nature and practical interests. This proposal is composed of two elements. First, based on our past studies on droplet collision dynamics, we will investigate the topic further by using liquids mixed with a small amount of surfactant. Surfactant has been applied in engineering situations to change surface tension significantly while keeping almost invariant the other properties such as density and viscosity. This enables us to extract exclusively the effect of capillary force on the behavior of droplet impact and to manipulate the outcome. Furthermore, we recently found that addition of surfactant could change the interfacial structure and render distinct collision results, e.g., to prevent coalescence, between droplets or interfaces in gases; this shall raise fundamental interest in the roles of Marangoni stresses due to gradients of surface tension and intermolecular forces. In this regard, for the second part, we will extend the realization to microfluidics where the interactions between interfaces are essentially dominated by such forces. Regarding the emerging significance of using multi-phase flows in micro/nano devices to conduct various tasks such as screening, carrying, and encapsulation of different media, we are concerned with the transport of dispersed phases in the continuous phase under the constraint of narrowed confinement. This would be a pioneering work with integration of our long-time experience on the subject and innovative implementation of surfactant in liquid-gas systems. In addition to a promising course leading to new techniques and methods for controlling the interaction between interfaces, we expect that success of this project shall help further our comprehension for the underlying physics of droplet collision and yield prospective utilization in industry.雙液滴碰撞界面活性劑多相流液滴微流體二相微尺度流binary droplet collisionsurfactantmultiphase flowdroplet microfluidicstwo-phase microflows