Regensburg 2022 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 15: Solid-Liquid Interfaces 2: Structure and Spectroscopy

O 15.3: Vortrag

Montag, 5. September 2022, 15:45–16:00, S054

Hydration layers at the graphite-water interface: Attraction or confinement? — Hagen Söngen¹, Ygor Morais Jaques², Lidija Zivanovic², Sebastian Seibert¹, •Ralf Bechstein¹, Peter Spijker², Hiroshi Onishi³, Adam S. Foster^{2, 4}, and Angelika Kühnle¹ — ¹Physical Chemistry I, Bielefeld University, Germany — ²COMP Centre of Excellence, Department of Applied Physics, Aalto University, Helsinki, Finland — ³Department of Chemistry, Kobe University, Japan — ⁴Division of Electrical Engineering and Computer Science, Kanazawa University, Japan

Water molecules at solid surfaces typically arrange in layers. The physical origin of the hydration layers is usually explained by (1) the attraction between the surface and the water and/or (2) the confinement of water due to the presence of the surface. While attraction is specific for the particular solid-solvent combination, confinement is a general effect at surfaces. A differentiation between the two effects is critical for interpreting hydration structures. At the graphite-water interface, the solid-solvent attraction is often considered to be negligible. Nevertheless, we observe hydration layers using three-dimensional atomic force microscopy at the graphite-water interface. We use Monte Carlo simulations to explain why confinement alone could cause the formation of hydration layers. With molecular dynamics simulations, we show that at ambient conditions, there is a significant graphite-water attraction which is pivotal for the formation of layers at the graphite-water interface.

[1] H. Söngen et al., Physical Review B, 100 (2019) 205410