Although experimental and theoretical studies have addressed the question of wetting properties graphene, actual value contact angle water on an isolated graphene monolayer remains unknown. While recent literature indicates that graphite is in range 90–95°, it has been suggested may either be as high 127° or moderately enhanced comparison with graphite. With support classical molecular dynamics simulations using empirical force-fields, we develop argumentation to show unrealistic estimate a...

Molecular dynamics simulations with an all-atom model were carried out to study the ionic liquid 1-n-butyl-3-methylimidazolium hexafluorophosphate, [bmim][PF6]. Analysis was characterize a number of structural and dynamic properties. It is found that hydrogen bonds are weaker than expected, as indicated by their short lifetimes, which due fast rotational motion anions. Transport properties such ion diffusion coefficients conductivity also measured on basis long trajectories, good agreement...

The second edition of “Molecular Driving Forces. Statistical Thermodynamics in Biology, Chemistry, Physics and Nanoscience” by Ken A. Dill Sarina Bromberg is an exciting statistical mechanics t...

Silica nanoparticles (NPs) embedded in atactic polystyrene (PS) are simulated using coarse-grained (CG) potentials obtained via iterative Boltzmann inversion (IBI). The parametrized and validated on of 2 kDa (i.e., chains containing 20 monomers). It is shown that the CG transferable between different systems. structure polymer strongly influenced by NP. Layering, chain expansion, preferential orientation segments as well entire found. extent structural perturbation depends details system:...

Different model Lennard-Jones solid-liquid interfaces have been considered. In the systems, either interaction strength between solid and liquid was varied, or topography of surface modified. all situations, interfacial free energy variations with respect to a reference interface were quantified by means thermodynamic integration method [F. Leroy et al., Macromol. Rapid Commun. 30, 864 (2009)], referred as phantom-wall method. Additionally, liquid-vapor determined. This result combined...

The question of the effect surface heterogeneities on evaporation liquid droplets from solid surfaces is addressed through nonequilibrium molecular dynamics simulations. mechanism behind contact line pinning which still unclear discussed in detail nanoscale. Model systems with Lennard-Jones interaction potential were employed to study nanometer-sized cylindrical a flat surface. heterogeneity was modeled alternating stripes equal width but two chemical types. first type leads angle 67°, and...

The question of the parametrization interfacial nonbonded interactions for heterogeneous solid–liquid systems is addressed through example water on graphene surfaces. We suggest that a reference value work adhesion WSL rather than corresponding wetting contact angle should be quantity to reproduce molecular simulations when deriving and testing interaction parameters. A relationship between adsorption energy established almost independently model. It shown this also holds graphite. ability...

We introduce a methodology, referred to as the dry-surface method, calculate work of adhesion heterogeneous solid-liquid interfaces by molecular simulation. This method employs straightforward thermodynamic integration approach reversible turn off attractive part actual interaction potential. It is formulated in such way that it may be used either evaluate ability force fields reproduce reference values or optimize force-field parameters with target quantities. The methodology tested case...

Self-diffusion coefficients for a series of n-alkanes adsorbed in silicalite zeolite have been obtained by equilibrium molecular dynamics. Simulations were carried out using rigid and flexible frameworks. It is shown that flexibility affects differently adsorbate transport properties according to alkane length loading. enhanced the lowest loadings shortest alkanes, namely methane n-butane, while no effect observed n-hexane n-octane diffusion.

Soret coefficients and mass diffusion of three states the n-pentane–n-decane mixture have been measured by thermal forced Rayleigh scattering (TDFRS) are compared with molecular dynamics simulations values. Both equilibrium (EMD), synthetic (S-NEMD), boundary driven (BD-NEMD) nonequilibrium techniques applied to compute phenomenological transport relevant effect. It is found that statistical error on cross-coefficients using dynamical S-NEMD too high enable any comparison experiments,...

The dynamics of Keggin polyoxoanions in aqueous solution the presence monovalent cations is analyzed through molecular simulations. Together with structural information yielding radial distribution functions Li(+), Na(+), and K(+) three polyoxometalates (POMs) bearing 3-, 4-, 5- charges, diffusion coefficient these POMs calculated. We found that effect microscopic details solvent a key aspect to interpreting dynamic data because competition between electrostatic interactions ions stability...

A method to compute the interfacial excess free energy of systems where a liquid phase is interacting with solid presented. The calculations are carried out by means molecular dynamics simulations. algorithm based on thermodynamic integration scheme that reversibly turns flexible atomistically detailed surface interacts into flat and allows calculation variation in Gibbs energy. approach probed applying it model system Lennard-Jones particles comparing previous similar systems.

The thermal conductivity in a set of mass-graded nanosized model systems has been studied by nonequilibrium molecular dynamics (MD) simulations order to understand the phenomenon rectification that detected externally mass-loaded nanotubes. We have found preferred direction heat transport nanotubes occurs from light heavy atoms while opposite transfer is observed anharmonic single-file chains. Mass-graded polyacetylenelike chains behave like as long mass gradient held backbone atoms. with...

Molecular dynamics simulations of Lennard-Jones particles have been performed to study the evaporation behavior nanodroplets on heated substrates. The influence liquid-substrate interaction strength properties was addressed. Our results show that, during temperature-raising evaporation, gas is always hotter than droplet. In contrast usual experimental conditions, droplet sizes in our are nanometer scale range and substrates ideally smooth chemically homogeneous. As a result, no pinning...

The effect of the three-phase contact-line curvature on evaporation mechanism nanoscopic droplets from smooth and chemically homogenous substrates is studied by molecular dynamics simulations. Spherical droplets, whose contact line curved, cylindrical radius infinite, are compared. It found that takes place at constant angle, while spherical evaporate simultaneous reduction their area angle. This independent substrate-liquid interaction strength. dependence can be rationalized with help...

The effect of nanoroughness on contact angles and pinning is investigated experimentally numerically for low-energy surfaces. Nanoroughness introduced by chemical vapor deposition tetraethoxysilane was quantified scanning force microscopy. Addition a root-mean-square roughness 2 nm flat surface can increase the angle after fluorination semifluorinated silane up to 30°. On other hand, improve or impair liquid repellency superhydrophobic surfaces that were made from assembled raspberry...

We introduce an analytical model to rapidly determine the thermal conductivity reduction due mass disorder in nanomaterials. Although this simplified classical depends only on masses of different atoms, it adequately describes changes transport as concentrations these atoms vary. Its predictions compare satisfactorily with nonequilibrium molecular dynamics simulations (14)C-(12)C carbon nanotubes well previous other materials. present a simple tool quantitatively estimate decrease that is...

The present work aims to contribute the understanding at a molecular level of origin hydrophobic nature surfaces exhibiting roughness nanometer scale. Graphite-based smooth and model whose dimension stretches from few angstroms nanometers were used in order generate Cassie Wenzel wetting states water. corresponding solid−liquid surface free energies computed by means dynamics simulations. energy water−smooth graphite was found be −12.7 ± 3.3 mJ/m2, which is reasonable agreement with value...

We investigated the solid-liquid work of adhesion water on a model silica surface by molecular dynamics simulations, where methodology previously developed to determine through thermodynamic integration was extended system with long-range electrostatic interactions between solid and liquid. In agreement previous studies, increased when magnitude polarity increased. On other hand, we found that comparing two systems without interactions, which were set have approximately same total...

The thermal rectification in nanotubes with a mass gradient is studied by reverse non-equilibrium molecular dynamics simulations. We predict preferred heat flow from light to heavy atoms which differs the preferential direction one-dimensional monoatomic systems. This behavior of explained anharmonicities caused transverse motions are stronger at low-mass end. present simulations show an enhanced increasing tube length, diameter and gradient. Implications findings for applied topics...

We study the role of solid-liquid interface thermal resistance (Kapitza resistance) on evaporation rate droplets a heated surface by using multiscale combination molecular dynamics (MD) simulations and analytical continuum theory. parametrize nonbonded interaction potential between perfluorohexane (C6F14) face-centered-cubic solid to reproduce experimental wetting behavior C6F14 black chromium through work adhesion (quantity directly related angle). The conductances (100) (111) substrates...

Reverse nonequilibrium molecular dynamics and equilibrium simulations were carried out to compute the shear viscosity of pure ionic liquid system [bmim][PF 6] at 300 K. The two methods yielded consistent results which also compared experiments. showed that reverse (RNEMD) methodology can successfully be applied computation highly viscous liquids. Moreover, this study provides a validation atomistic force-field developed by Bhargava Balasubramanian ( J. Chem. Phys. 2007, 127, 114510 ) for...

A simple theoretical model is proposed for computing the interfacial entropy of water at rigid hydrophobic surfaces. The entropy, which not considered in mean field models static wettability, evaluated from fluctuations water–surface dispersion energy single particle level and represents configurational bias imposed on fluid molecules by attractive external potential a solid wall. comparison with results obtained molecular dynamics simulations shows that quantitatively describes loss when...

We address the question of how reducing number degrees freedom modifies interfacial thermodynamic properties heterogeneous solid-liquid systems. consider example n-hexane interacting with multi-layer graphene which we model both fully atomistic and coarse-grained (CG) models. The CG models are obtained by means conditional reversible work (CRW) method. thermodynamics these is characterized adhesion WSL calculated dry-surface methodology through molecular dynamics simulations. find that CRW...

Owing to its peculiar electronic properties, molybdenum disulfide (MoS2) has been the subject of a growing number studies in recent years. In applications, this material and other transition metal dichalcogenides (TMDs) may have interact with liquid or polymer phase as well solutions biomolecules. It is therefore primary importance understand wetting adhesion properties TMDs. Starting from existing models, we derive Lennard-Jones parameters for interaction between water basal plane MoS2 that...