Water adsorption on hydrogenated Si(111) surfaces

Lange, Björn; Posner, R.; Pohl, Karsten; Thierfelder, Christian; Grundmeier, Guido; Blankenburg, Stephan; Schmidt, Wolf Gero

doi:10.1016/j.susc.2008.10.030

Cited by 27 publications

(40 citation statements)

References 28 publications

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“…30 Besides electronic effects, the consideration of surface energies in our model is essential. Methods based on adsorption energies only, 48,60,61 although they appear well adapted for the determination of water-wetting properties, seems not to be adequate for the determination of wetting properties using a metal as a probe.…”

Section: Discussionmentioning

confidence: 99%

Nonwetting Behavior of Al–Co Quasicrystalline Approximants Owing to Their Unique Electronic Structures

Anand

Fournée

Prévot

et al. 2020

ACS Appl. Mater. Interfaces

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Good wetting is generally observed for liquid metals on metallic substrates, while poor wetting usually occurs for metals on insulating oxides. In this work, we report unexpected large contact angles for lead on two metallic approximants to decagonal quasicrystals, namely, Al 5 Co 2 and Al 13 Co 4 . Intrinsic surface wettability is predicted from first principles, using a thermodynamic model based on the Young equation, and validated by the good agreement with experimental measurements performed under ultra-high vacuum by scanning electron microscopy. The atomistic details of the atomic and electronic structures at the Pbsubstrate interface, and the comparison with Pb(111)/Al(111), underline the influence of the specific electronic structures of quasicrystalline approximants on wetting. Our work suggests a possible correlation of the contact angles with the density of states at the Fermi energy and paves the way for a better fundamental understanding of wettability on intermetallic substrates, which has potential consequences in several applications such as supported catalysts, protective coatings, or crystal growth.

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Section: Discussionmentioning

confidence: 99%

Nonwetting Behavior of Al–Co Quasicrystalline Approximants Owing to Their Unique Electronic Structures

Anand

Fournée

Prévot

et al. 2020

ACS Appl. Mater. Interfaces

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“…However, the difference of cos θ between nm and nm-H can be computed assuming that γ SV is identical for both systems. Following the argumentation in ref 58 , we estimate γ SL by the interaction energy given in eq 12 per unit area.…”

Section: Charge Fittingmentioning

confidence: 99%

Wetting of water on hexagonal boron nitride@Rh(111): a QM/MM model based on atomic charges derived for nano-structured substrates

Golze

Hutter

Iannuzzi

2015

Phys. Chem. Chem. Phys.

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The wetting of water on corrugated and flat hexagonal boron nitride (h-BN) monolayers on Rh(111) is studied within a hybrid quantum mechanics/molecular mechanics (QM/MM) approach. Water is treated by QM methods, whereas the interactions between liquid and substrate are described at the MM level. The electrostatic properties of the substrate are reproduced by assigning specifically generated partial charges to each MM atom. We propose a method to determine restrained electrostatic potential (RESP) charges that can be applied to periodic systems. Our approach is based on the Gaussian and plane waves algorithm and allows an easy tuning of charges for nano-structured substrates. We have successfully applied it to reproduce the electrostatic potential of the corrugated and flat h-BN/Rh(111) known as nanomesh. Molecular dynamics simulations of water films in contact with these substrates are performed and structural and dynamic properties of the interfaces are analyzed. Based on this analysis and on the interaction energies between water film and substrate, we found that the corrugated nanomesh is slightly more hydrophilic. On a macroscopic scale, we expect a smaller contact angle for a droplet on the corrugated surface. The wetting of water on corrugated and flat hexagonal boron nitride (h-BN) monolayers on Rh (111) is studied within a hybrid quantum mechanics/molecular mechanics (QM/MM) approach. Water is treated by QM methods, whereas the interactions between liquid and substrate are described at the MM level. The electrostatic properties of the substrate are reproduced by assigning specifically generated partial charges to each MM atom. We propose a method to determine restrained electrostatic potential (RESP) charges that can be applied to periodic systems. Our approach is based on the Gaussian and plane waves algorithm and allows an easy tuning of charges for nano-structured substrates. We have successfully applied it to reproduce the ESP of the corrugated and flat (h-BN)/Rh(111) known as nanomesh. Molecular dynamics simulations of water films in contact with these substrates are performed and structural and dynamic properties of the interfaces are analyzed. Based on these analyses and on the interaction energies between water film and substrate, we found that the corrugated nanomesh is slightly more hydrophilic. On a macroscopic scale, we predict a smaller contact angle for a droplet on the corrugated surface.

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“…Organization of water into an ordered layer on mica surfaces for example has been extensively studied, and recently Spagnoli et al 29 were able to image an ice-like layer of water molecules on mica under ambient conditions using AFM. Studies of water adsorption on hydrogen-terminated Si(111) 30,31 found that water-water interactions were stronger than water-substrate interactions. Studies of adsorbed water layers on hydrophilic silicon oxide 32,33 revealed different structures were formed depending on the level of relative humidity (RH), with an ice-like water monolayer observed below 30% RH, an additional transitional monolayer of water on the ice-like base for RH between 30% and 60%, and liquid water at the interface with air for higher values of RH.…”

Section: -10mentioning

confidence: 99%

Nanoscale condensation of water on self-assembled monolayers

et al. 2011

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We demonstrate that water is almost universally present on apparently dry self-assembled monolayers, even on those considered almost hydrophobic by conventional methods such as water contact goniometry. The structure and kinetics of nanoscale water adsorption onto these surfaces were investigated using X-ray and neutron reflectometry, as well as atomic force microscopy. Condensation of water on hydrophilic surfaces under ambient conditions formed a dense sub-nanometre surface layer; the thickness of which increased with exponentially limiting kinetics. Tapping mode AFM measurements show the presence of nanosized droplets that covered a small percentage (∼2%) of the total surface area, and which became fewer in number and larger in size with time. While low vacuum pressures (∼10-8 bar) at room temperature did nothing to remove the adsorbed water from these monolayers, heating to temperatures above 65 °C under atmospheric conditions did lead to evaporation from the surface. We demonstrate that water contact angle measurements are not necessarily sensitive to the presence of nanoscale adsorbed water and do not vary with time. For the most part they are a poor indicator of the kinetics and the amount of water condensation onto these surfaces at the molecular level. In summary, this study reveals the need to exclude air containing even trace amounts of water vapor from such surfaces when characterizing using techniques such as X-ray reflectometry. 2011 The Royal Society of Chemistry. We demonstrate that water is almost universally present on apparently dry self-assembled monolayers, even on those considered almost hydrophobic by conventional methods such as water contact goniometry. The structure and kinetics of nanoscale water adsorption onto these surfaces were investigated using X-ray and neutron reflectometry, as well as atomic force microscopy. Condensation of water on hydrophilic surfaces under ambient conditions formed a dense sub-nanometre surface layer; the thickness of which increased with exponentially limiting kinetics. Tapping mode AFM measurements show the presence of nanosized droplets that covered a small percentage ($2%) of the total surface area, and which became fewer in number and larger in size with time. While low vacuum pressures ($10 À8 bar) at room temperature did nothing to remove the adsorbed water from these monolayers, heating to temperatures above 65 C under atmospheric conditions did lead to evaporation from the surface.We demonstrate that water contact angle measurements are not necessarily sensitive to the presence of nanoscale adsorbed water and do not vary with time. For the most part they are a poor indicator of the kinetics and the amount of water condensation onto these surfaces at the molecular level. In summary, this study reveals the need to exclude air containing even trace amounts of water vapor from such surfaces when characterizing using techniques such as X-ray reflectometry.

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Water adsorption on hydrogenated Si(111) surfaces

Cited by 27 publications

References 28 publications

Nonwetting Behavior of Al–Co Quasicrystalline Approximants Owing to Their Unique Electronic Structures

Nonwetting Behavior of Al–Co Quasicrystalline Approximants Owing to Their Unique Electronic Structures

Wetting of water on hexagonal boron nitride@Rh(111): a QM/MM model based on atomic charges derived for nano-structured substrates

Nanoscale condensation of water on self-assembled monolayers

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