| Thu October 12th 2017 15:00 – 16:00 ZH286 | Seminar | Marangoni effect at fluid interfaces: some perspectives and applications Cunjing Lv |
Details:Interfacial phenomena resulted from the Marangoni effect have a great importance in both nature and industrial processes. Extensive research has been devoted to understanding the role of the Marangoni effect in liquid film spreading, droplet/particle transport and manipulation, and flow instabilities. In this talk, I will try to shed some light on the understanding of the Marangoni effect at the fluid interfaces by presenting two subjects in our recent work: (i) Controlling trajectories of nano-/micro particles using light-actuated Marangoni flow; (ii) Liquid plug formation from heated binary mixtures in capillary tubes. In the first study, we focus on trapping and manipulation of nano- and microparticles using optically controlled interfacial flows, a method named “Light-Actuated Marangoni Tweezer (LAMT)”. We demonstrate that particles with diameters ranging from 20 nm to 10 μm can be manipulated by translating a light beam along a liquid surface, and we are able to handle a number of particles in parallel by creating an optical “landscape” consisting of a multitude of laser spots. In addition, the inherent advantages of LAMTs are discussed by comparing with the conventional optical tweezers. In the second study, we turn to some unique phenomena associated with the solutal Marangoni effect in confined space. Various morphologies, such as liquid films, rings and plugs have been observed. Evolution of the liquid surfaces in conjunction with a key phenomenon – the transition from a liquid ring and a plug, is revealed using the concept of a quasi-static minimal energy surface that becomes unstable when the liquid volume exceeds a specific value. These studies facilitate to acquire ideas to a number of follow-up studies, such as opening up new avenues for the large-area manipulation and patterning of very small objects, and achieving new insights to interfacial hydrodynamics occurring in constraints in microfluidics. | ||
