Dynamics of capillary evaporation. I. Effect of morphology of hydrophobic surfaces

Luzar, Alenka; Leung, Kevin

doi:10.1063/1.1290478

Cited by 115 publications

(143 citation statements)

References 72 publications

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“…Concerning self-diffusion, it is easier at the vicinity of hydrophobic interfaces. Recent studies have shown that a layer of water vapour exists at the vicinity of hydrophobic surfaces (Mezger et al 2006) confirming also different results obtained by simulations of the molecular dynamics (Luzar and Leung 2000). Also, it was observed that the dynamics of hydration water is different in the case of peptides that differ only by the presence of a hydrophobic chain in the first case as shown in the cases of N-acetyl-leucine-methylamide and N-acetyl-glycinemethylamide (Russo et al 2008).…”

Section: Resultssupporting

confidence: 67%

Dynamics of hydration water in proteins

Teixeira

2009

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Abstract. Thermodynamic and transport properties of liquid water are determined essentially by inter-molecular hydrogen bonds and their dynamics. Because the molecular dynamics depends mostly on geometric constrains and dynamics of hydrogen bonds, it is shown that a simple statistics on the number of bonds, including at the vicinity of hydrophilic substrates describes well the temperature dependence of water diffusion on the surface of a small peptide.Experiments were performed by incoherent quasi-elastic neutron scattering giving information about the hydrogen bond lifetime and the residence time of the water molecules. In order to study the interactions between water molecules and a small hydrophobic peptide (an assembly of five monomers of alanine), the hydration level is changed step by step. The only motion of the first single water molecule of the structure is due to hydrogen libration. The first two added water molecules bind with the hydrophilic site of the peptide and have only the dynamics of the bond breaking. The other hydration molecules show fast diffusive motions on the surface of the peptide.

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Section: Resultssupporting

confidence: 67%

Dynamics of hydration water in proteins

Teixeira

2009

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“…[13][14][15] It has also been possible to study the dynamical behavior for such models through the use of dynamic Monte Carlo simulations with Kawasaki dynamics, which models dynamics generated by nearest neighbor hopping processes. Examples include phase separation dynamics for confined liquid mixtures, 10,11 the kinetics of nonwetting liquids in pores, 16,17 and the relaxation dynamics during gas adsorption in porous glasses. 15,18 These approaches are an efficient alternative to very time consuming nonequilibrium molecular dynamics calculations.…”

Section: Introductionmentioning

confidence: 99%

Mean field kinetic theory for a lattice gas model of fluids confined in porous materials

Monson

2008

The Journal of Chemical Physics

100

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We consider the mean field kinetic equations describing the relaxation dynamics of a lattice model of a fluid confined in a porous material. The dynamical theory embodied in these equations can be viewed as a mean field approximation to a Kawasaki dynamics Monte Carlo simulation of the system, as a theory of diffusion, or as a dynamical density functional theory. The solutions of the kinetic equations for long times coincide with the solutions of the static mean field equations for the inhomogeneous lattice gas. The approach is applied to a lattice gas model of a fluid confined in a finite length slit pore open at both ends and is in contact with the bulk fluid at a temperature where capillary condensation and hysteresis occur. The states emerging dynamically during irreversible changes in the chemical potential are compared with those obtained from the static mean field equations for states associated with a quasistatic progression up and down the adsorption/desorption isotherm. In the capillary transition region, the dynamics involves the appearance of undulates ͑adsorption͒ and liquid bridges ͑adsorption and desorption͒ which are unstable in the static mean field theory in the grand ensemble for the open pore but which are stable in the static mean field theory in the canonical ensemble for an infinite pore.

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“…Simulation examples of such confinement-induced drying (50) range from nanotubes (51) to plates (28,45,(52)(53)(54)(55)(56)(57)(58)(59) and the interfaces between proteins (30,60) to collapsing polymers (25)(26)(27). Associated with these surface-induced drying transitions are nanometer-scale fluctuations in the local water density (27), resulting in detectable locally liquid-like and vapor-like phases.…”

Section: Discussionmentioning

confidence: 99%

Static and dynamic correlations in water at hydrophobic interfaces

Mittal

Hummer

2008

Proc. Natl. Acad. Sci. U.S.A.

137

144

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We study the static and dynamic properties of the water-density fluctuations in the interface of large nonpolar solutes. With the help of extensive molecular dynamics simulations of TIP4P water near smooth spherical solutes, we show that for large solutes, the interfacial density profile is broadened by capillary waves. For purely repulsive solutes, the squared width of the interface increases linearly with the logarithm of the solute size, as predicted by capillary-wave theory. The apparent interfacial tension extracted from the slope agrees with that of a free liquid-vapor interface. The characteristic length of local density fluctuations is Ϸ0.5 nm, measured along the arc, again consistent with that of a free liquid-vapor interface. Probed locally, the interfacial density fluctuations exhibit large variances that exceed those expected for an ideal gas. Qualitatively consistent with theories of the free liquid-vapor interface, we find that the water interface near large and strongly nonpolar solutes is flickering, broadened by capillarywave fluctuations. These fluctuations result in transitions between locally wet and dry regions that are slow on a molecular time scale.capillary waves ͉ drying transition ͉ hydrophobic effect ͉ surface tension T he hydration structure and thermodynamics of simple nonpolar solutes in water is central to a molecular understanding of many biological self-assembly processes, including protein folding and the formation of lipid membranes (1-4). To understand the water-induced conformational changes in biopolymers that lead to functional structures, it is critical to study not only the effects of water on these molecules but also the reverse, i.e., the modified behavior of water in the vicinity of these molecules. To avoid the inherent chemical and structural complexities of present in biological molecules, it is instructive to consider model systems with tunable degrees of freedom. Arguably the simplest such model system is a smooth spherical particle immersed in a water bath (5-18). Such a rudimentary solute model captures two key factors in solvation, the size of the solute and the strength of its interactions with water.Small, methane-sized solutes are accommodated by water with only minor disruptions of the bulk hydrogen-bond network. The resulting small-solute hydration thermodynamics has been predicted successfully by approaches that take into account the molecular-scale density fluctuations in bulk water, including scaled-particle theory (5, 19) (see ref. 20 for a recent review), Pratt-Chandler theory (8), the Gaussian field model (21), an information theory model (22), and Lum-Chandler-Weeks (LCW) theory (23). With the addition of a large repulsive solute, it becomes impossible for water molecules to maintain their bulk hydrogen-bond structure (24), which also affects the wetting behavior. At ambient conditions the contact theorem predicts a near-zero water density at a flat hard wall (5). Based on this rigorous limit and an interpolation formula, Stillinger anticipated that...

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Dynamics of capillary evaporation. I. Effect of morphology of hydrophobic surfaces

Cited by 115 publications

References 72 publications

Dynamics of hydration water in proteins

Dynamics of hydration water in proteins

Mean field kinetic theory for a lattice gas model of fluids confined in porous materials

Static and dynamic correlations in water at hydrophobic interfaces

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