Formation of Amorphous PbCrO4 Nanoparticles Depending on the Quantitative Control of Interfacial Water

2021 ◽  
Author(s):  
Chunli Wang ◽  
Zhihao Zhang ◽  
Xiaoheng Fu ◽  
Jing Zhang ◽  
Jan K. G. Dhont
Keyword(s):  
Bulk Water ◽  
Interfacial Water

Interfacial water confined in the microemulsions behaviors different to normal bulk water and could affect the reactions involved at the interface. In this work, the content of interfacial and bulk...

The three types of liquid water in the surface of present Mars

2009 ◽  
Vol 9 (1) ◽  
pp. 45-49 ◽  
Author(s):  
D. Möhlmann
Keyword(s):  
Solid State ◽  
Liquid Water ◽  
Bulk Water ◽  
Pure Liquid ◽  
Interfacial Water ◽  
Biological Processes ◽  
Undercooled Liquid ◽  
Liquid Bulk ◽  
Physical Chemical

AbstractThermodynamics teaches that pure liquid bulk water cannot stably exist on the surface of Mars. However, it is shown by thermodynamic arguments that liquid water can exist, at least temporarily, in the upper surface of Mars, in form of: (a) undercooled liquid interfacial water (ULI water); (b) undercooled liquid water in cryo-brines; and (c) liquid bulk water (due to solid-state greenhouse subsurface melting) in the subsurface of ice areas, which are covered by a lid of solid ice only. The presence of these forms of liquid water on present Mars is discussed in detail and in view of the possible consequences for physical, chemical and eventual biological processes.

scholarly journals Anomalously low dielectric constant of confined water

Science ◽  
2018 ◽  
Vol 360 (6395) ◽  
pp. 1339-1342 ◽  
Author(s):  
L. Fumagalli ◽  
A. Esfandiar ◽  
R. Fabregas ◽  
S. Hu ◽  
P. Ares ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Bulk Water ◽  
Dead Layer ◽  
Low Dielectric Constant ◽  
Interfacial Water ◽  
Confined Water ◽  
Low Dielectric ◽  
Out Of Plane ◽  
Atomically Flat ◽  
Rotational Freedom

The dielectric constant ε of interfacial water has been predicted to be smaller than that of bulk water (ε ≈ 80) because the rotational freedom of water dipoles is expected to decrease near surfaces, yet experimental evidence is lacking. We report local capacitance measurements for water confined between two atomically flat walls separated by various distances down to 1 nanometer. Our experiments reveal the presence of an interfacial layer with vanishingly small polarization such that its out-of-plane ε is only ~2. The electrically dead layer is found to be two to three molecules thick. These results provide much-needed feedback for theories describing water-mediated surface interactions and the behavior of interfacial water, and show a way to investigate the dielectric properties of other fluids and solids under extreme confinement.

Anomalously High Proton Conduction of Interfacial Water

2020 ◽  
Author(s):  
Vasily Artemov ◽  
Ece Uykur ◽  
Pavel Kapralov ◽  
Alexei Kiselev ◽  
Keith Stevenson ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Bulk Water ◽  
Interfacial Water ◽  
High Proton ◽  
New Type ◽  
Porous Matrices ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Physical And Chemical ◽  
Separations Science

Water at the solid-liquid interface exhibits an anomalous ionic conductivity and dielectric constant compared to bulk water. Both phenomena still lack a detailed understanding. Here, we report radiofrequency measurements and analyses of the electrodynamic properties of interfacial water confined in nano-porous matrices formed by diamond grains of various sizes, ranging from 5 nm to 0.5 μm in diameter. Contrary to bulk water, the charge-carrying protons/holes in interfacial water are not mutually screened allowing for higher mobility in the external electric field. Thus, the protonic conductivity reaches a maximum value, which can be five orders of magnitude higher than that of bulk water. Our results aid in the understanding of physical and chemical properties of water confined in porous materials, and pave the way to the development of new type of highly-efficient proton-conductive materials for applications in electrochemical energy systems, membrane separations science and nano-fluidics.

MODELING OF INTERFACIAL BEHAVIOR OF WATER AND ORGANICS

2013 ◽  
Vol 12 (07) ◽  
pp. 1350059 ◽  
Author(s):  
VLADIMIR M. GUN'KO
Keyword(s):  
Density Functional ◽  
Bound Water ◽  
Water Structure ◽  
Structural Features ◽  
Bulk Water ◽  
Interfacial Water ◽  
Interfacial Behavior ◽  
Functional Theory ◽  
H Nmr

Modeling of water structure at a surface of different adsorbents, as well as an influence of dissolved compounds or co-adsorbates on bound water, is of importance to understand the temperature dependence of the characteristics of bound water, especially at T < 273 K, in comparison with bulk water. 1 H NMR spectra giving useful information on the water structure can be obtained using different ways such as experimental measurements, direct ab initio and density functional theory (DFT) calculations or estimation using semiempirical calculations and appropriate calibration functions. Here, application of the last approach is analyzed with respect to a variety of relatively large hydrated systems. Despite the simplicity of this approach, it gives quantitative characterization of structural features of interfacial water and effects of different co-adsorbates and adsorbent surfaces on bound water.

scholarly journals Ice-like water supports hydration forces and eases sliding friction

2016 ◽  
Vol 2 (8) ◽  
pp. e1600763 ◽  
Author(s):  
Nishad Dhopatkar ◽  
Adrian P. Defante ◽  
Ali Dhinojwala
Keyword(s):  
Sliding Friction ◽  
Water Structure ◽  
Water Layer ◽  
Bulk Water ◽  
Interfacial Water ◽  
Confined Water ◽  
Surfactant Monolayers ◽  
Sum Frequency ◽  
Charged Surfaces ◽  
Hydration Forces

The nature of interfacial water is critical in several natural processes, including the aggregation of lipids into the bilayer, protein folding, lubrication of synovial joints, and underwater gecko adhesion. The nanometer-thin water layer trapped between two surfaces has been identified to have properties that are very different from those of bulk water, but the molecular cause of such discrepancy is often undetermined. Using surface-sensitive sum frequency generation (SFG) spectroscopy, we discover a strongly coordinated water layer confined between two charged surfaces, formed by the adsorption of a cationic surfactant on the hydrophobic surfaces. By varying the adsorbed surfactant coverage and hence the surface charge density, we observe a progressively evolving water structure that minimizes the sliding friction only beyond the surfactant concentration needed for monolayer formation. At complete surfactant coverage, the strongly coordinated confined water results in hydration forces, sustains confinement and sliding pressures, and reduces dynamic friction. Observing SFG signals requires breakdown in centrosymmetry, and the SFG signal from two oppositely oriented surfactant monolayers cancels out due to symmetry. Surprisingly, we observe the SFG signal for the water confined between the two charged surfactant monolayers, suggesting that this interfacial water layer is noncentrosymmetric. The structure of molecules under confinement and its macroscopic manifestation on adhesion and friction have significance in many complicated interfacial processes prevalent in biology, chemistry, and engineering.

scholarly journals Anomalously High Proton Conduction of Interfacial Water

2020 ◽  
Author(s):  
Vasily Artemov ◽  
Ece Uykur ◽  
Pavel Kapralov ◽  
Alexei Kiselev ◽  
Keith Stevenson ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Bulk Water ◽  
Interfacial Water ◽  
High Proton ◽  
New Type ◽  
Porous Matrices ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Physical And Chemical ◽  
Separations Science

Water at the solid-liquid interface exhibits an anomalous ionic conductivity and dielectric constant compared to bulk water. Both phenomena still lack a detailed understanding. Here, we report radiofrequency measurements and analyses of the electrodynamic properties of interfacial water confined in nano-porous matrices formed by diamond grains of various sizes, ranging from 5 nm to 0.5 μm in diameter. Contrary to bulk water, the charge-carrying protons/holes in interfacial water are not mutually screened allowing for higher mobility in the external electric field. Thus, the protonic conductivity reaches a maximum value, which can be five orders of magnitude higher than that of bulk water. Our results aid in the understanding of physical and chemical properties of water confined in porous materials, and pave the way to the development of new type of highly-efficient proton-conductive materials for applications in electrochemical energy systems, membrane separations science and nano-fluidics.

scholarly journals Neutron scattering and microscopy studies of the structure and dynamics of water near a nanostructured hydrophilic copper oxide surface

2019 ◽  
Author(s):  
◽  
James Robert Torres
Keyword(s):  
Heat Transfer ◽  
Cupric Oxide ◽  
Melting Behavior ◽  
Bulk Water ◽  
Neutron Imaging ◽  
Oxide Surface ◽  
Interfacial Water ◽  
Time Resolved ◽  
Structure And Dynamics ◽  
Performance Of Heat Transfer

Recently, it has been shown that superhydrophilic coatings of "grass-like" cupric oxide (CuO) nanostructures can significantly improve the thermal performance of heat transfer devices known as oscillating heat pipes (OHPs). The origin of this enhanced performance is currently unknown, but it is believed to be attributed to the thin film of interfacial water supported by the nanostructures that coat the OHP's interior surface. The aim of this work is to investigate the microscopic origin of enhanced heat transfer at the CuO surface by studying the structure, morphology, freezing/melting behavior, and dynamics of the water in proximity to the CuO coating over time and length scales that span picosecond-to-seconds and angstroms-to-millimeters, respectively . ... Our results demonstrate that water near superhydrophilic CuO nanostructures exhibits low-temperature anomalies in its structure and dynamics at the molecular level-a direction of research that has both applied and fundamental interest. The significantly altered structure and dynamics of the interfacial water could affect the boundary conditions for bulk water motion inside of an OHP during its operation. To test this hypothesis, we have proposed time-resolved neutron imaging experiments to characterize the kinetics of water oscillations in CuO-coated OHPs.

The Hofmeister effect and the behaviour of water at interfaces

1985 ◽  
Vol 18 (4) ◽  
pp. 323-422 ◽  
Author(s):  
Kim D. Collins ◽  
Michael W. Washabaugh
Keyword(s):  
Charge Transfer ◽  
Water Molecule ◽  
Water Structure ◽  
Water Layer ◽  
Bulk Water ◽  
Water Molecules ◽  
Interfacial Water ◽  
Hydrogen Bonding Interactions ◽  
Air Water Interface ◽  
Polar Solutes

SUMMARYStarting from known properties of non-specific salt effects on the surface tension at an air–water interface, we propose the first general, detailed qualitative molecular mechanism for the origins of ion-specific (Hofmeister) effects on the surfacepotential differenceat an air–water interface; this mechanism suggests a simple model for the behaviour of water at all interfaces (including water–solute interfaces), regardless of whether the non-aqueous component is neutral or charged, polar or non-polar. Specifically, water near an isolated interface is conceptually divided into three layers, each layer being 1 water-molecule thick. We propose that the solute determines the behaviour of the adjacent first interfacial water layer (I1); that the bulk solution determines the behaviour of the third interfacial water layer (I3), and that bothI1andI3compete for hydrogen-bonding interactions with the intervening water layer (I2), which can be thought of as a transition layer. The model requires that a polar kosmotrope (polar water-structure maker) interact withI1more strongly than would bulk water in its place; that a chaotrope (water-structure breaker) interact withI1somewhat less strongly than would bulk water in its place; and that a non-polar kosmotrope (non-polar water-structure maker) interact withI1much less strongly than would bulk water in its place.We introduce two simple new postulates to describe the behaviour ofI1water molecules in aqueous solution. The first, the ‘relative competition’ postulate, states that anI1water molecule, in maximizing its free energy (—δG), will favour those of its highly directional polar (hydrogen-bonding) interactions with its immediate neighbours for which the maximum pairwise enthalpy of interaction (—δH) is greatest; that is, it will favour the strongest interactions. We describe such behaviour as ‘compliant’, since anI1water molecule will continually adjust its position to maximize these strong interactions. Its behaviour towards its remaining immediate neighbours, with whom it interacts relatively weakly (but still favourably), we describe as ‘recalcitrant’, since it will be unable to adjust its position to maximize simultaneously these interactions. The second, the ‘charge transfer’ postulate, states that the strong polar kosmotrope–water interaction has at least a small amount of covalent character, resulting in significant transfer of charge from polar kosmotropes to water–especially of negative charge from Lewis bases (both neutral and anionic); and that the water-structuring effect of polar kosmotropes is caused not only by the tight binding (partial immobilization) of the immediately adjacent (I1) water molecules, but also by an attempt to distribute among several water molecules the charge transferred from the solute. When extensive, cumulative charge transfer to solvent occurs, as with macromolecular polyphosphates, the solvation layer (the layer of solvent whose behaviour is determined by the solute) can become up to 5- or 6-water-molecules thick.We then use the ‘relative competition’ postulate, which lends itself to simple diagramming, in conjunction with the ‘charge transfer’ postulate to provide a new, startlingly simple and direct qualitative explanation for the heat of dilution of neutral polar solutes and the temperature dependence of relative viscosity of neutral polar solutes in aqueous solution. This explanation also requires the new and intriguing general conclusion that as the temperature of aqueous solutions is lowered towards o °C, solutes tend to acquire a non-uniform distribution in the solution, becoming increasingly likely to cluster 2 water molecules away from other solutes and surfaces (the driving force for this process being the conversion of transition layer water to bulk water). The implications of these conclusions for understanding the mechanism of action of general (gaseous) anaesthetics and other important interfacial phenomena are then addressed.

scholarly journals Role of interfacial water in adhesion, friction, and wear—A critical review

Friction ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 1-28
Author(s):  
Lei Chen ◽  
Linmao Qian
Keyword(s):  
Friction And Wear ◽  
Normal Load ◽  
Water Layer ◽  
Adsorbed Water ◽  
Bulk Water ◽  
Interfacial Water ◽  
Molecular Configuration ◽  
Water Condensation ◽  
Adhesion Friction

Abstract Surficial water adsorption and interfacial water condensation as natural phenomena that can alter the contact status of the solid interface and tribological performances are crucial in all length scales, i.e., from earthquakes to skating at the macroscale level and even to micro/nano-electromechanical systems (M/NEMS) at the microscale/nanoscale level. Interfacial water exhibits diverse structure and properties from bulk water because of its further interaction with solid surfaces. In this paper, the evolutions of the molecular configuration of the adsorbed water layer depending on solid surface chemistry (wettability) and structure, environmental conditions (i.e., relative humidity and temperature), and experimental parameters (i.e., sliding speed and normal load) and their impacts on tribological performances, such as adhesion, friction, and wear, are systematically reviewed. Based on these factors, interfacial water can increase or reduce adhesion and friction as well as facilitate or suppress the tribochemical wear depending on the water condensation kinetics at the interface as well as the thickness and structure of the involved interfacial water.

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