The boron nitride nanomesh is a corrugated monolayer of hexagonal boron nitride (h-BN) on Rh(111), and forms because of the lattice mismatch between the two materials. Here, we demonstrate how the nanomesh can be used as a model system in the study of stiction and adhesion of a sessile drop of liquid, six orders of magnitude larger than the lattice constant of the corrugation. Electrochemical intercalation of atomic hydrogen between the h-BN monolayer and the rhodium substrate weakens the Rh–N bond and reversibly switches off its corrugation, and with it in-plane electrostatic dipole rings that are responsible for its adsorptive properties. The intercalation is proven directly by electrochemistry-to-vacuum transfer of a deuterium-loaded sample followed by thermal desorption spectroscopy. By performing dynamic contact angle measurements under electrochemical potential control within the sessile drop, we are able to link the change in surface morphology to a 10% change in adhesion forces between the substrate and the liquid drop. Quantitative agreement is found with experiments of water adsorption on the nanomesh, if the flat state is taken equivalent with unfavourable adsorption on the wire regions. The relatively simple structure of the boron nitride nanomesh allows accurate descriptions down to the atomic level, and makes the nanomesh an attractive model system for full-scale theoretical analyses of switchable surfaces, wetting, friction and lubrication.

Boron nitride nanomesh model system for stiction and adhesion

253rd National Meeting (2017)

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