Abstract of the talk// Understanding how water, ions, and surfaces interact across length scales is central to electrochemistry, nanofluidics, and catalysis. In particular, the impact of hydrogen-bond network termination and interfacial charges on the arrangement of counterions and water has been the subject of intense debate. Across three studies, Mischa and his team have established a molecular-level picture of structure and dynamics at aqueous interfaces under confinement and electrostatic perturbation.

They demonstrated that, down to the angstrom-scale confinement, interfacial effects entirely determine the organization of confined water, disrupting bulk-like hydrogen bonding and producing asymmetric environments due to wall contact [Nature Commun. 16, 7288 (2025)]. These findings establish that nanofluidic behavior is governed not by the confined volume, but by its bounding interfaces. They extended this picture to show that even nominally neutral materials, such as hexagonal boron nitride, acquire a spontaneous surface charge at the aqueous interface [J. Am. Chem. Soc. 147, 30107 (2025)].

This intrinsic charging, observed in other solids as well, indicates that the formation of an electric double layer (EDL) is nearly universal at solid–liquid boundaries. Finally, the scientists resolved the ultrafast dynamics of the aqueous EDL using femtosecond-resolved optical spectroscopy, showing that ionic rearrangements occur within tens of picoseconds — faster than diffusion-limited models predict [Science 388, 405 (2025)]. Together, these studies provide a molecularly consistent understanding of how interfacial polarization, confinement, and charge collectively define water’s behavior in nanofluidic and electrochemical environments.