Department of Chemistry Seminar – Dr. Vida Jamali

Dr. Vida Jamali   

University of California Berkeley

“Imaging, Learning, and Engineering of Soft Matter Systems at the Nanoscale”

The motion and dynamics of nanoparticles and macromolecules in bulk and at interfaces is of fundamental importance in physics, chemistry, and biology. Liquid phase transmission electron microscopy (LPTEM) is an emerging technique which enables nanoscale visualization of the motion and dynamics of single nanoparticles in liquid environment with an unprecedented spatial and temporal resolution. However, in order to develop LPTEM as a tool for in situ single nanoparticle and macromolecule tracking, we first need to understand how the electron beam of a transmission electron microscope affects the particle motion in the liquid environment and near surfaces.

In this talk, I will present my recent work on studying the anomalous diffusive motion of a model system of gold nanorods dispersed in water and moving near the silicon nitride membrane of a commercial liquid cell in a broad range of electron beam dose rates. By leveraging the power of convolutional deep neural networks inspired by canonical statistical tests, I show that there is a crossover in diffusive behavior of nanoparticles in LPTEM from fractional Brownian motion at low dose rates, resembling diffusion in a viscoelastic medium, to continuous time random walk at high dose rates, resembling diffusion on an energy landscape with trapping sites. I will then discuss how this work forms the foundation to study equilibrium and nonequilibrium dynamic processes for a broad range of nanoparticles, interfaces, and fluids in chemical and biological systems.

Bio

Dr. Vida Jamali is a postdoctoral researcher at the University of California Berkeley where she works with Prof. Paul Alivisatos and in collaboration with Prof. Kranthi Mandadapu. Vida received her PhD in Chemical and Biomolecular Engineering from Rice University, working on the phase behavior and morphology of carbon nanotube liquid crystalline solutions with Prof. Matteo Pasquali. Vida’s research uses a combination of experimental, theoretical, and computational tools such as liquid phase transmission electron microscopy, rheology, statistical mechanics, and machine learning, to study the dynamics of nanostructured soft matter systems. Vida was selected as a rising star in soft and biological matter by the University of Chicago, MRSEC in 2021.