APhMS: EAS Trailblazers Department Seminar

**Refreshments at 10:45am in Spalding Lobby

Abstract:

The phase transformation between liquid water and ice is among the most fundamental processes that shape the Earth's ecosphere and define human activities. However, the ice-water interface has never been imaged at molecular resolution. This talk discusses our recent breakthroughs in imaging ice crystals and the ice water interface at angstrom-level resolution. We developed a cryo-liquid-cell approach to prepare stable single-crystalline ice Ih sections for high-resolution electron imaging. We show that ice is highly tolerant to nanoscale defects, such as misoriented subdomains and trapped gas bubbles, stabilized by molecular scale structural motifs. Gas bubbles can dynamically nucleate, grow, migrate, dissolve, and coalesce under electron irradiation and be monitored in situ near a steady state. Lattice-resolved imaging of melting and crystallization dynamics at the ice-water interface further provides critical insights into facet-dependent kinetics and local molecular fluctuations. This work provides new research paradigms to the theory, modeling, and forecasting of ice crystallization and melting in environmental, biological, and material systems.

More about the Speaker:

Jingshan S. Du is a Washington Research Foundation Postdoctoral Fellow at Pacific Northwest National Laboratory. His research spans crystal formation and transformation pathways, correlative and in situ electron microscopy, and complex atomic configurations in nanostructures. Du received a Ph.D. in Materials Science and Engineering from Northwestern University in 2021 and a B.Sc. in Engineering from Zhejiang University Chu Kochen Honors College in 2015. Du is an Associate Editor of Frontiers for Young Minds, a barrier-breaking journal publishing scientific articles for young audiences. He serves on the Community Board of Nanoscale Horizons and the Early Career Board of ACS Biomaterials Science & Engineering. He will chair the 2025 Gordon Research Seminar: Crystal Growth and Assembly.