The evolution in graphitic surface wettability with first-principles quantum simulations: the counterintuitive role of water

Capillary condensation of water from vapor is an everyday phenomenon which has a wide range of scientific and technological implications. Many aspects of capillary condensation are not well understood such as the structure of interfacial water, the existence of distinct properties of confined water, or the validity of the Kelvin equation at nanoscale. We note the absence of high-spatial resolution images inside a meniscus. Here, we develop an AFM-based method to provide in situ atomic-scale resolution maps of the solid–water interface of a nanomeniscus (80–250 nm 3 ). The separation between the first two hydration layers on graphite is 0.30 nm, while on mica it is 0.28 nm. Those values are very close to the ones expected for the same surfaces immersed in bulk water. Thus, the hydration layer structure on a crystalline surface is independent of the water volume.

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“… 24 The airborne contamination of the graphite surface might also be affected by the adsorption of water from the air. 22 …”

mentioning

confidence: 99%

In Situ Atomic-Scale Imaging of Interfacial Water under 3D Nanoscale Confinement

Uhlig

García

2021

Nano Lett.

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“…Lu et al linked the dynamic functional theory (DFT)-predicted adhesive energy at solid/liquid interface and cohesive energy at liquid/liquid interface with DFT atomic force microscope (AFM)-predicted force of adhesion through the Young–Dupré equation and established the basis of quantum surface wettability theory by combining two independent atomic-level quantum physics simulation methodologies [ 46 ]. They used quantum physics via density functional theory simulation [ 47 ] to directly evaluate how the surface wettability of graphite is influenced.…”

Section: Discussionmentioning

confidence: 99%

Effects of Bonding Agents on Metal-Ceramic Bond Strength of Co-Cr Alloys Fabricated by Selective Laser Melting

et al. 2020

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Bonding agents have been developed to improve bond strength between ceramic and Co-Cr metal. The aim of this study was to investigate the influence of two bonding agents on bond strength of Co-Cr metal fabricated by selective laser melting (SLM). Bond strength was determined by a three-point bending test, and the interfaces of the metal and ceramic, before and after the bending test, were observed by optical microscopy and scanning electron microscopy (SEM) to determine the thickness of the oxide layer and amount of ceramic remaining. To analyze the elemental composition of the bonding agents and fractured surfaces, energy dispersive X-ray spectroscopy (EDS) was used. Co-Cr specimens with bonding agent showed significantly higher bond strength than Co-Cr specimens without bonding agents. The fractured surfaces of most specimens showed mixed failure, but failure mode varied according to bonding agent and fabrication type. Specimens from groups treated with bonding agents had significantly higher remaining ceramic fractions on fractured Co-Cr alloys than specimens from groups that did not receive bonding agent. Mass amounts of silicone (Si) and titanium (Ti) on the fractured alloy surfaces were also different among specimens according to method of fabrication and presence of bonding agent. Together, the results suggest that application of bonding agent to 3D printed Co-Cr metal increases bond strength with ceramics.

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“…2d (i)), which results in the hydrophobicity increasing over time ( Fig. 2d (ii)) 28 . Nonreactive adventitious hydrocarbons absorbed from the air also modulate the wettability of 2D materials.…”

Section: Intrinsic Perturbation Of the Wetting Behavior Of 2d Materialsmentioning

confidence: 93%

“…d (i) Time-resolved schematic of the water adsorption on the graphite surface in an ambient environment. (ii) Comparison of the time-resolved DFT-predicted WCAs on graphite surfaces with different numbers of adsorbed water layers and experimentally measured static WCAs with different aging times 28 . e (i) Temporal evolution of the WCA measured on a graphene/copper sample.…”

Section: Extrinsic Tuning Of the Wettability Of 2d Materialsmentioning

confidence: 99%

Interaction of 2D materials with liquids: wettability, electrochemical properties, friction, and emerging directions

et al. 2020

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The emergence of two-dimensional (2D) materials as functional surfaces for sensing, electronics, mechanics, and other myriad applications underscores the importance of understanding 2D material-liquid interactions. The thinness and environmental sensitivity of 2D materials induce novel surface forces that drive liquid interactions. This complexity makes fundamental 2D material-liquid interactions variable. In this review, we discuss the (1) wettability, (2) electrical double layer (EDL) structure, and (3) frictional interactions originating from 2D material-liquid interactions. While many 2D materials are inherently hydrophilic, their wettability is perturbed by their substrate and contaminants, which can shift the contact angle. This modulation of the wetting behavior enables templating, filtration, and actuation. Similarly, the inherent EDL at 2D material-liquid interfaces is easily perturbed. This EDL modulation partially explains the wettability modulation and enables distinctive electrofluidic systems, including supercapacitors, energy harvesters, microfluidic sensors, and nanojunction gating devices. Furthermore, nanoconfinement of liquid molecules at 2D material surfaces arising from a perturbed liquid structure results in distinctive hydrofrictional behavior, influencing the use of 2D materials in microchannels. We expect 2D material-liquid interactions to inform future fields of study, including modulation of the chemical reactivity of 2D materials via tuning 2D material-liquid interactions. Overall, 2D material-liquid interactions are a rich area for research that enables the unique tuning of surface properties, electrical and mechanical interactions, and chemistry. Origin of 2D material interactions with liquids The ideal interaction between a surface and a liquid is dictated by surface forces. Surface forces can be subdivided into three components: van der Waals forces, which exist at any interface between solids and liquids; electrostatic interactions, which exist between charged or polar surfaces and fluids; and structural forces, principally hydrogen bonding 1. These interactions influence the wetting behavior and determine whether the interaction with water is hydrophilic or hydrophobic, control the electronic structure at the liquid-solid interface, influence the frictional interaction, and modulate the chemical activity. However, this ideal picture of the surface interactions is complicated when considering surface heterogeneities, including roughness 2 and contamination 3 , which interfere with the formation of an equilibrium configuration between the liquid and the surface, leading to eccentric behaviors, including superwetting, superslipping, and superhydrophobicity. These surface heterogeneities also allow the surface liquid interactions to be tuned, enabling an array of applications in sensing, chemical transport, and actuation. Two-dimensional (2D) materials, which are extremely thin, have unique electrical properties, and have a tendency to deform and accumulate contamination during proce...

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The evolution in graphitic surface wettability with first-principles quantum simulations: the counterintuitive role of water

Cited by 23 publications

References 40 publications

In Situ Atomic-Scale Imaging of Interfacial Water under 3D Nanoscale Confinement

In Situ Atomic-Scale Imaging of Interfacial Water under 3D Nanoscale Confinement

Effects of Bonding Agents on Metal-Ceramic Bond Strength of Co-Cr Alloys Fabricated by Selective Laser Melting

Interaction of 2D materials with liquids: wettability, electrochemical properties, friction, and emerging directions

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