Controlling interfacial structure and dynamics of phase separating fluid mixtures is key to creating diverse functional materials. Traditionally, this is accomplished by controlling interface chemistry, through the presence of surface-modifying amphiphilic agents. Using a phase separating a mixture of active and passive fluids, we study how mechanical activity controls soft interfaces. Feedback between the stresses generated in the fluid’s bulk and low interfacial tension gives rise to giant interfacial fluctuations and non-inertial traveling waves that propagate along the phase boundary. Active interfaces arrest the phase separation dynamics, creating finite-size droplet distribution maintained by the balance of the enhanced coalescence of smaller motile droplets and the spontaneous break-up of larger ones. When in contact with a solid wall, active interfaces also exhibit non-equilibrium wetting transitions, where the fluid climbs the wall against gravity. These results demonstrate the promise of mechanically-driven interfaces for creating a new class of soft active matter.
About the Speaker
Zvonimir Dogic's research interests are primarily experimental and span both equilibrium and non-equilibrium phenomena. He uses various biological architectures to create novel soft materials that exhibit physics that is not easily accessible by using purely synthetic methods. He actively collaborates with numerous theorists as well as experimentalists from different disciplines both within and outside of physics. He obtained his BA and Ph.D. in Physics from Brandeis University. After postdoctoral positions in Research Center Julich, Germany, and the University of Pennsylvania, he was a Research Fellow at Rowland Institute at Harvard. In 2007 he started as an Assistant Professor in Physics at Brandeis University, and in 2017 he moved to the University of California at Santa Barbara.
Host: Professor Gabriel Juarez
* Times, dates, and titles are subject to change. Check mechanical.illinois.edu for updated information.
This seminar counts toward the requirements for ME 590 and TAM 500.