Molecular Dynamics Simulation of Atomic Force Microscopy at the Water-Muscovite Interface: Hydration Layer Structure...

Area of Science:

• Surface Science
• Materials Science
• Computational Chemistry

Background:

• Atomic force microscopy (AFM) enables 3D atomic-scale detection of buried liquid-solid interfaces.
• Muscovite surfaces are ideal AFM models due to their atomically flat basal planes.
• Direct quantitative links between AFM force profiles and interfacial structures remain challenging.

Purpose of the Study:

• To investigate the relationship between muscovite-water interfacial structure and AFM force profiles.
• To utilize molecular dynamics simulations with a capped carbon nanotube (CNT) AFM tip.
• To elucidate the contributions of individual water layers to the total measured force.

Main Methods:

• Performing molecular dynamics simulations.
• Using a capped carbon nanotube (CNT) as an atomic force microscopy (AFM) tip.
• Analyzing divided force profiles to show contributions from each water layer.

Main Results:

• The first hydration layer dominates the total force, even when disrupted.
• The lateral structure of the first hydration layer replicates the muscovite surface structure.
• Local water density profiles correlate with detected force structures, though tip disturbance causes discrepancies.

Conclusions:

• AFM force profiles reflect fundamental atomic structures of hydration layers.
• The first water layer plays a crucial role in AFM force measurements at liquid-solid interfaces.
• Discrepancies between force and density profiles highlight the impact of AFM tip-surface interactions.