Watching self-assembly dynamics at the nanoscale using liquid-phase TEM

Dr Qian Chen, Assistant Professor of Materials Science and Engineering at the University of Illinois at Urbana-Champaign, will talk about how liquid-phase transmission electron microscopy can be used to image self-assembly dynamics at the nanoscale.

Abstract

Self-assembly of nanoscale building blocks is an efficient strategy to construct complexity in biology and engineering, which produces extremely rich phases, reconfigurability and associated functions. Yet the quantitative prediction of their ensemble architectures and formation kinetics remains a challenge due to technical impediments.

Here we use a new nanoscopic imaging technique, liquid phase transmission electron microscopy, to directly image the self-assembly of colloidal nanoparticles in solution, one-by-one in real-time. Depending on solvent conditions, a single type of anisotropic nanoparticles can lead to a wide variety of final structures not previously predicted: linear and cyclic “polymeric” chains, hierarchical plastic crystals, and highly ordered solids.

In-situ monitoring of the dynamic pathways together with computation reveals interesting and novel phenomena in these systems due to inherent many-body coupling and discreteness at the nanoscale. We expect our study to open new opportunities in understanding the conformation, phase behaviors and collective dynamics on the nanometer length scale that is not accessible using other means.

About Dr Qian Chen

Professor Qian Chen received her B.S. in Chemistry from Peking University, China (2007), and her PhD in Materials Science and Engineering from UIUC with Prof. Steve Granick (2012). Her doctoral research focused on developing new “bottom-up” strategies for materials construction.

She was among the first to encode multiplexed information into colloids in a “Janus” or “patchy” fashion, and to assemble them into functional materials. She found these materials exhibit properties that were new and exciting to the community, including “supracolloidal” reactivity and entropic stabilization of ordering.

In 2012, she obtained a Miller postdoc fellowship and worked with Prof. Paul Alivisatos at UC Berkeley. There she explored broadly structural and functional dynamics at nanoscale, including liquid phase TEM and plasmonics based bio-sensing. She pioneered the efforts in unprecedented in situ imaging of biomolecular transformation at nm resolution, and the spatial mapping of nanoscale interactions among colloidal nanocrystals.

In 2015 she joined the faculty of the University of Illinois at Urbana-Champaign as Assistant Professor of Materials Science and Engineering and affiliated Assistant Professor of Chemistry.

More Information

Please contact Dr Rachel Sparks for more information:

rachel.sparks@manchester.ac.uk