Hongbo Zhao, Ph.D.
Assistant Professor
Department of Physics and Chemistry
University of California, San Diego
Seminar Information
Active interfaces appear across living and synthetic systems—from microswimmers, algae and bacteria to ciliated airways, collective cell behavior, microrobotic swimmers, and reconstituted cytoskeletal materials. In each case, forces generated locally at interfaces can organize motion and reshape matter on much larger scales.
In this talk, I will discuss how interfacial activity produces emergent dynamics. I will show how patterned activity in multicomponent droplets can generate translation, rotation, oscillations, and topological rearrangements, with symmetry providing a framework for understanding and programming these motions. I will also discuss actively sheared interfaces, where tangential active stresses drive a Kelvin–Helmholtz-like instability.
I will then turn to droplets interacting with deformable fibers through elastocapillarity - the same basic competition between surface tension and elasticity that makes wet hairs bundle, and that also plays a role when membraneless organelles deform and organize chromatin in the cell nucleus. This coupling points toward a broader framework for understanding how actively migrating cells interact with extracellular matrices.
Hongbo Zhao is an Assistant Professor in the Departments of Physics and Chemistry at UC San Diego. His research combines theoretical and computational approaches to study emergent phenomena in soft and living matter, with a focus on active matter, phase separation, hydrodynamics, and data-driven modeling. He received his Ph.D. from MIT and conducted postdoctoral research at Princeton University before joining UC San Diego.