Newton black films as wetting systems

Tarazona, P.; Martínez, H. L.; Chacón, Enrique; Bresme, Fernando

doi:10.1103/physrevb.85.085402

Cited by 12 publications

(8 citation statements)

References 35 publications

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“…Nevertheless, the nonanalytic dependence 0 (q) − 0 (0) ∼ q (rather than q 2 ) for low q, and the strongly negative value of 0 (q) for q = 1.9/σ indicate the formation of large domains with relatively sharp boundaries that signal the instability of the macroscopic film. A similar behavior was observed, e.g., on Newton black films, which behave as a wetting system [30], due to the existence of domains (droplets) with different sizes and widths.…”

Section: Cw Fluctuations At the Edge Of Wetting Layersmentioning

confidence: 59%

Mesoscopic Hamiltonian for the fluctuations of adsorbed Lennard-Jones liquid films

et al. 2015

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We use Monte Carlo simulations of a Lennard-Jones fluid adsorbed on a short-range planar wall substrate to study the fluctuations in the thickness of the wetting layer, and we get a quantitative and consistent characterization of their mesoscopic Hamiltonian, H [ξ ]. We have observed important finite-size effects, which were hampering the analysis of previous results obtained with smaller systems. The results presented here support an appealing simple functional form for H[ξ ], close but not exactly equal to the theoretical nonlocal proposal made on the basis a generic density-functional analysis by Parry and coworkers. We have analyzed systems under different wetting conditions, as a proof of principle for a method that provides a quantitative bridge between the molecular interactions and the phenomenology of wetting films at mesoscopic scales.

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Section: Cw Fluctuations At the Edge Of Wetting Layersmentioning

confidence: 59%

Mesoscopic Hamiltonian for the fluctuations of adsorbed Lennard-Jones liquid films

et al. 2015

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“…The intrinsic sampling method (ISM) proposed by Chacón and Tarazona was used to construct the intrinsic surface. The S atoms of SDS were used as pivots characterizing positions of the surface. ,, The surface with minimal surface area passing through all the pivots is constructed with the ISM method. , The cutoff wavelength λ c was set to 0.5 nm, approximately corresponding to the peak position of the radial distribution function (RDF) between S atoms (Figure ). However, it should be noted that the surface passing through S atoms pivots are in fact several layers beneath the water/vapor interface, as disclosed by Abranko-Rideg et al Selecting different atoms as pivots can lead to different characterizations of the intrinsic surface.…”

Section: Simulation Details and Analytic Methodsmentioning

confidence: 99%

Specific Counterion Effects on the Atomistic Structure and Capillary-Waves Fluctuation of the Water/Vapor Interface Covered by Sodium Dodecyl Sulfate

Chen

Liu

et al. 2014

J. Phys. Chem. C

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The structure of the water/vapor interface covered by a sodium dodecyl sulfate (SDS) monolayer can be remarkably affected by salts in aqueous phase. Molecular dynamics simulations have been performed to reveal the microstructure of the interface with different salts, including NaCl, CaCl2, and MgCl2. The bending modulus κ of the interface exhibits the order: with MgCl2 < with CaCl2 < with NaCl ≈ without salt, while the surface tension γ almost remains unchanged. The smaller κ characterizes larger interfacial fluctuation. In the systems with CaCl2 or MgCl2, the intrinsic density of Na+ adsorbed beside the monolayer is much lower than that without salt or with NaCl due to the adsorption of Ca2+ or Mg2+. However, less Ca2+ or Mg2+ ions enter the hydration shells of sulfate groups while Na+ ions normally coordinate the sulfate groups together with water. So in the systems with CaCl2 or MgCl2, sulfate groups are less bridged by ions and more solvated by water. Thus, the alkyl tails become more disordered. The above microstructure change with the addition of divalent ions leads to more fluctuated interface. This finding helps in understanding the mechanism of the influence of salts on the stability of foam films.

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“…Structures of NBFs have been well studied by experiments [4][5][6] and molecular dynamics (MD) simulations. [7][8][9][10][11][12][13] As shown in experiments 6 and MD simulations, 9,13 dipole orientations of water preferentially point towards the anionic groups at the interface. As a result, water exhibits an anomalous dielectric response, 13,14 which is thought to be the origin of the hydration force.…”

Section: Introductionmentioning

confidence: 77%

“…Water originally between adhesive layers is expelled forming a droplet inside the film. 11,12 The unusual hydration force and adhesive behavior of NBFs are inherently correlated with the solvation of ionic groups in water. Water in the hydration layer of ionic groups not only exhibits special structure, but also dynamics behaviors, i.e., slower reorientational and translational motions of water.…”

Section: Introductionmentioning

confidence: 99%

Slow dynamics of water confined in Newton black films

Chen

Liu

et al. 2015

Phys. Chem. Chem. Phys.

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Slowdown of translational and reorientational dynamics of water confined in Newton black films (NBFs) is revealed by molecular dynamics simulations. As a film becomes thinner, both translational and reorientational dynamics become slower. The polarization of water molecules in the macroscopic electrostatic field across the NBF and the coordination of Na(+) ions and surfactant anionic groups around water molecules concertedly lead to slowdown of water dynamics. The polarization effect is obvious for water not coordinated by Na(+) ions, which exhibits reorientational dynamics depending on initial dipole orientations. Na(+) ions and surfactant anionic groups retard dynamics of surrounding water by decreasing the hydrogen bond exchange probability and increasing the viscosity of water. The dependences of translational and reorientational dynamics on coordination environments of water are similar. Dynamics of water in positions close to the interfaces of NBFs are mainly retarded by Na(+) ions and surfactant anionic groups, while the macroscopic polarization effect plays the main role in influencing water dynamics in positions far from the interfaces. This study sheds light on the improvement of knowledge about the water dynamics slowdown mechanism in similar environments like reverse micelles and lamellar structures.

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Newton black films as wetting systems

Cited by 12 publications

References 35 publications

Mesoscopic Hamiltonian for the fluctuations of adsorbed Lennard-Jones liquid films

Mesoscopic Hamiltonian for the fluctuations of adsorbed Lennard-Jones liquid films

Specific Counterion Effects on the Atomistic Structure and Capillary-Waves Fluctuation of the Water/Vapor Interface Covered by Sodium Dodecyl Sulfate

Slow dynamics of water confined in Newton black films

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