Hydrogen bonding and molecular orientation at the liquid–vapour interface of water

Cipcigan, Flaviu; Sokhan, V. P.; Jones, Andrew; Crain, Jason; Martyna, Glenn

doi:10.1039/c4cp05506c

Cited by 42 publications

(45 citation statements)

References 35 publications

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“…4. 49 Accordingly, the dipole vector of a water molecule points towards the surface when the angle is 180 • , and it points away from the surface when the angle is 0 • . Similar to the previous studies in the literature, 50,51 only the water molecules in the first hydration shell (within 5 Å distance from the wall) were taken into consideration as the interface region.…”

Section: Resultsmentioning

confidence: 99%

Electric field controlled transport of water in graphene nano-channels

Celebi

Barışık

Beşkök

2017

The Journal of Chemical Physics

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Motivated by electrowetting-based flow control in nano-systems, water transport in graphene nano-channels is investigated as a function of the applied electric field. Molecular dynamics simulations are performed for deionized water confined in graphene nano-channels subjected to opposing surface charges, creating an electric field across the channel. Water molecules respond to the electric field by reorientation of their dipoles. Oxygen and hydrogen atoms in water face the anode and cathode, respectively, and hydrogen atoms get closer to the cathode compared to the oxygen atoms near the anode. These effects create asymmetric density distributions that increase with the applied electric field. Force-driven water flows under electric fields exhibit asymmetric velocity profiles and unequal slip lengths. Apparent viscosity of water increases and the slip length decreases with increased electric field, reducing the flow rate. Increasing the electric field above a threshold value freezes water at room temperature.

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Section: Resultsmentioning

confidence: 99%

Electric field controlled transport of water in graphene nano-channels

Celebi

Barışık

Beşkök

2017

The Journal of Chemical Physics

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“…This implies that a significant fraction of the water molecules at the interface possess dangling OH bonds that are protruding out of the water phase into the vacuum. In later studies, dangling OH groups at the interface have been confirmed by SFG mea-surements of others [22,23,63,64] and molecular dynamics (MD) simulations [31,33,34,36,38,45,53,65]. Nevertheless, other experiments using X-ray absorption [21,24] and SFG spectroscopy [20], as well as ab initio MD (AIMD) simulations [36] have found a much larger fraction of "accepter-only" water configurations.…”

Section: Introductionmentioning

confidence: 83%

Structure and Dynamics of the Instantaneous Water/Vapor Interface Revisited by Path-Integral and Ab Initio Molecular Dynamics Simulations

et al. 2015

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The structure and dynamics of the water/vapor interface is revisited by means of path-integral and second-generation Car-Parrinello ab initio molecular dynamics simulations in conjunction with an instantaneous surface definition [Willard, A. P.; Chandler, D. J. Phys. Chem. B 2010, 114, 1954]. In agreement with previous studies, we find that one of the OH bonds of the water molecules in the topmost layer is pointing out of the water into the vapor phase, while the orientation of the underlying layer is reversed. Therebetween, an additional water layer is detected, where the molecules are aligned parallel to the instantaneous water surface.

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“…However, in the present study, we will adopt a two-state model [63][64][65][66]. To describe the structure and thermodynamic properties of liquid water within the montmorillonite matrix, we adopt the so-called two-state model [67,68], which assumes two different states of intermolecular bonding: One is an ice-like state where water molecules are more ordered, and another one is a more densely packed arrangement where hydrogen bonds are distorted [69][70][71]. Here, we apply the two-state model and we partition the H 2 O molecules into: (i) H 2 O molecules with two OH groups both hydrogen-bonded to a tetrahedral network, and (ii) H 2 O molecules whose hydrogen bond is broken or weakened by distortion.…”

Section: Analysis and Discussionmentioning

confidence: 99%

Self-Assembly Processes in Hydrated Montmorillonite by FTIR Investigations

Caccamo

Mavilia

et al. 2020

Materials

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Experimental findings obtained by FTIR and Raman spectroscopies on montmorillonite-water mixtures at three concentration values are presented. To get some insight into the hydrogen bond network of water within the montmorillonite network, FTIR and Raman spectra have been collected as a function of time and then analyzed following two complementary approaches: An analysis of the intramolecular OH stretching mode in the spectral range of 2700–3900 cm−1 in terms of two Gaussian components, and an analysis of the same OH stretching mode by wavelet cross-correlation. The FTIR and Raman investigations have been carried as a function of time for a montmorillonite-water weight composition (wt%) of 20–80%, 25–75%, and 35–65%, until the dehydrated state where the samples appear as a homogeneous rigid layer of clay. In particular, for both the FTIR and Raman spectra, the decomposition of the OH stretching band into a “closed” and an “open” contribution and the spectral wavelet analysis allow us to extract quantitative information on the time behavior of the system water content. It emerges that, the total water contribution inside the montmorillonite structure decreases as a function of time. However, the relative weight of the ordered water contribution diminishes more rapidly while the relative weight of the disordered water contribution increases, indicating that a residual water content, characterized by a highly structural disorder, rests entrapped in the montmorillonite layer structure for a longer time. From the present study, it can be inferred that the montmorillonite dehydration process promotes the layer self-assembly.

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Hydrogen bonding and molecular orientation at the liquid–vapour interface of water

Cited by 42 publications

References 35 publications

Electric field controlled transport of water in graphene nano-channels

Electric field controlled transport of water in graphene nano-channels

Structure and Dynamics of the Instantaneous Water/Vapor Interface Revisited by Path-Integral and Ab Initio Molecular Dynamics Simulations

Self-Assembly Processes in Hydrated Montmorillonite by FTIR Investigations

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