Physical Chemistry Seminar: Professor Qian Chen, University of Illinois Urbana-Champaign
About the Seminar
Electron Videography of Soft, Biological, and Energy Materials
My group studies the spatiotemporal heterogeneity of materials and addresses the associated science and technological questions of how to image it, quantify it, understand it, and engineer it for new properties, from the finest atomic scale to the particle assembly and composite scale. Specifically, we adapt a suite of electron videography methods (e.g., liquid-phase TEM, electron tomography, 4D-STEM) and machine-learning based data-mining to synthetic soft, biological, and energy related systems. In the first direction, we focus on the synthesis and phase behaviors of colloidal nanoparticles. We image the crystallization pathways in solution, where the discreteness and multi-scale coupling effects complicate the free energy landscape. Single particle tracking and simulations combined unravel a series of interesting dynamics at this length scale, such as non-classical nucleation, size-dependent crystal growth habits, and moiré patterning, enabling advanced crystal engineering. In the second direction, we study membrane proteins in their native lipid and liquid environment at the nanometer resolution. The proteins exhibit real-time “fingering” fluctuations, which we attribute to dynamic rearrangement of lipid molecules wrapping the proteins. The conformational coordinates of protein transformation obtained from the movies are used as inputs in our molecular dynamics simulations, to derive lipid-protein interactions. In the third direction, we further push direct imaging to separation membranes formed from interfacial polymerization as well as multivalent ion batteries, where microstructure heterogeneity leads to morphogenesis and distinct charge transport properties. Our studies on these systems reveal unified presence and importance of spatiotemporal heterogeneity in morphology, composition, structure, and functionality. Our suite of “electron videography” tools serve as the basis for imaging and manipulating materials in space and time at the nanoscale.
About the Speaker
Prof. Qian Chen is currently an associate professor and Racheff Scholar in the Department of Materials Science and Engineering at the University of Illinois at Urbana-Champaign. She obtained her PhD degree from the same department with Prof. Steve Granick (2012) and completed her postdoctoral research with Prof. Paul Alivisatos at the University of California, Berkeley, under a Miller Fellowship. She became a faculty in 2015 and since then has received awards for the research in her group, such as the Forbes 30 under 30 Science List (2016), the AFOSR YIP (2017), the NSF CAREER award (2018), the Sloan Research Fellow in Chemistry (2018), the ACS Unilever Award (2018), the Hanwha-TotalEnergies IUPAC Young Scientist Award (2022), the Soft Matter Lectureship (2023), the Provost's Award for Excellence in Graduate Student Mentoring (2024), and the MRS Outstanding Early-Career Investigator Award (2024). Her group’s research focuses on imaging, understanding, and engineering soft, biological, and energy materials at the nanoscale.