Dynamics of Compound Droplets: Rolling and Evaporation

  • Author / Creator
    Rahman, Muhammad Rizwanur
  • Superior control of multiphase micro-drops owns much of the future in microfluidic technology. Understanding the dynamics of such compound systems is the key to its large-scale applications. Interfacial interaction of a droplet at a liquid-fluid interface dictates its successful generation and stability. The knowledge of the interface dynamics creates a rich profusion of domains that were previously unexplored. The century-old power law, which was believed to be universal in governing temporal drop spreading on solid substrates, is seen to fail in predicting spreading on liquid-fluid interface. Rather a coalescence like behavior becomes imminent. The study of the fundamental physics of evaporation of double emulsion droplets and under liquid rolling dynamics are extensions of the successful generation technique. In contrast to the rigid body motion, dissipation inside and outside of a deformable drop always results in convoluted physics. While rolling on an incline, single-phase drops travel slower with increase in size. But a concealed direct dependency between the drop size and traveling velocity can be exposed by merely altering the medium resistance. Rolling motion of double emulsion droplets even affirms the presence of both of these dependencies and a control over the transition from one to the other is achievable. A threshold size limit for such a transition has been identified demonstrating that the dependency between drop size and its velocity is not unidirectional. This thesis further explores the evaporation of double emulsion droplets and identifies two new regimes of evaporation. Resurfacing of a daughter droplet from an evanescing drop preceded by sudden spreading are uncommon observations in the literature. Detailed comprehension of the resurfacing of micro-droplets provides a possibility to control the evaporation mode, which was considered to be a random occurrence in the past.

  • Subjects / Keywords
  • Graduation date
    Spring 2018
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.