Evolution of chemical and physical transformations under electron beams, light, and mechanical impact. – (Dominik Lungerich / CEMES / Seminar). – 21/11/2025, 11 H

Séminaire du CEMES

Dominik Lungerich, CEMES

Seminar CEMES, 21/11/2025, 11H

Summary
The advent of aberration-corrected transmission electron microscopy (AC-TEM) has revolutionized materials science and adjacent disciplines, enabling researchers to capture atomic-level details with unprecedented precision. Among these developments, single-molecule atomic-resolution time-resolved electron microscopy (SMART-EM) has emerged as a powerful approach to visualize dynamic events at the molecular and atomic scale in real time.

My research integrates these microscopic insights with chemical understanding—through the lens of an organic chemist—to elucidate reaction mechanisms driven by electron beams.[1–5] Using high-resolution imaging, complemented by image simulations and density functional theory calculations, we demonstrate the controlled formation of carbon nanostructures at the molecular level. These results establish electron-beam chemistry as a distinct and complementary approach to conventional thermal, photochemical, and mechanochemical methods.

Using light as an energy source, I investigate molecular photoswitches as building blocks for responsive and mechanically active materials.[6] Among them, azobenzenes—undergoing a pronounced geometrical change from ~1 nm (trans) to ~0.5 nm (cis)—represent some of the most promising actuators. Inspired by biological muscle systems, we tailor their response through dopants and environmental modulation, creating complex multiresponsive materials that can be triggered by stimuli beyond light alone.

Finally, mechanochemically assisted synthesis continues to gain importance in both academia and industry but remains limited by an incomplete understanding of reaction kinetics. In particular, dependencies on the type and dynamics of milling equipment are poorly understood and often overlooked. To address this, I identify critical kinetic parameters using kinematic models, enabling reproducibility and cross-comparison of mechanochemical reactions across commonly used planetary and mixer mills.[7]

Together, these studies illustrate how directed energy inputs—electronic, photonic, and mechanical—can drive and control chemical transformations with spatial and temporal precision, expanding the boundaries of molecular design and materials engineering.

References:

• [1] J.-Y. Yoon, D. Lungerich* et al., “Understanding Electron Beam-Induced Chemical Polymerization Processes of Small Organic Molecules Using Operando Liquid-Phase Transmission Electron Microscopy” ACS Nano 2025, 19, 10889–10901.
• [2] M. Lin, D. Lungerich*, J. Cheon* et al., “A magnetically powered nanomachine with a DNA clutch” Nat. Nanotechnol. 2024, 19, 646–651.
• [3] J. Park, D. Lungerich*, “Electron beam-induced demetallation of Fe, Co, Ni, Cu, Zn, Pd, and Pt metalloporphyrins: insights in e-beam chemistry and metal cluster formations” Phys. Chem. Chem. Phys. 2024, 26, 8051–8061.
• [4] H. Hoelzel, D. Lungerich* et al., “Time-resolved imaging and analysis of the electron beam-induced formation of an open-cage metallo-azafullerene” Nat. Chem. 2023, 15, 1444–1451.
• [5] T. Shimizu, D. Lungerich*, K. Harano*, E. Nakamura*, “Time-Resolved Imaging of Stochastic Cascade Reactions over a Submillisecond to Second Time Range at the Angstrom Level” J. Am. Chem. Soc. 2022, 144, 9797–9805.
• [6] A. Ayadi, D. Lungerich* et al., “Synthesis and Photophysical Analysis of Amphiphilic Azobenzene Surfactants for Photomechanical Actuation” Eur. J. Org. Chem. 2025, 28, e202500250.
• [7] O. F. Jafter, D. Lungerich* et al., “Navigating Ball Mill Specifications for Theory‐to‐Practice Reproducibility in Mechanochemistry” Angew. Chem. Int. Ed. 2024, e202409731