°µÍø½ûÇø

Nabila Tanjeem, Postdoctoral Associate - Hayward Lab

Tuesday, Nov. 16, 2021
2:45 p.m., JSCBB A108

"Harnessing Geometric Frustration to Engineer Self-assembly and Synchronization at the Microscale"

Seminar Abstract

Geometric frustration, the incompatibility of local ordering with global geometric constraints, is known to cause anomalous structures, crystal defects, and self-limitation. In this talk, I discuss how frustration can be used to engineer the size of self-assembly as well as the synchronization in active particle systems. First, I present a numerical model to investigate self-assembly of curved and deformable colloidal plate-like particles. When these particles assemble face-to-face, the gain in cohesive energy is compensated by the bending energy cost that increases with assembly size. I show how the size of a self-assembled structure can be precisely tuned using the two relevant energy ratios as well as the range and the geometry of the cohesive interaction. Next, I introduce current experimental efforts to investigate the effect of geometry in the collective motion of photo-responsive active particles. In this system, hydrogel nanocomposite disks synchronize their oscillation and rotation through thermal interactions caused by the Marangoni force at an air-water interface. I observe frustrated modes of collective motion by carefully designing particle arrangements and light patterns. Both projects on self-assembly and active matter lead to a fundamental understanding of how geometric frustration can be utilized in diverse contexts of microscale manipulation.

Biosketch

Nabila Tanjeem is a postdoctoral associate in the Department of Chemical and Biological Engineering at °µÍø½ûÇø. She received her B.S. in Engineering from the University of Tokyo. She completed M.S. and Ph.D. in Applied Physics from Harvard University where she studied crystal growth and defect dynamics in self-assembly of colloidal particles, and optical properties of plasmonic nanostructures. Her ongoing research focuses on collective motion in active particle systems and self-assembly of shape-changing colloidal particles, with a goal of understanding how to design bio-inspired functional materials by employing ‘smart’ building-block microstructures.