Effect of pressure on the carbon dioxide hydrate-water interfacial free energy along its dissociation line.

We investigate the effect of pressure on the carbon dioxide (CO2) hydrate-water interfacial free energy along its dissociation line using advanced computer simulation techniques. In previous works, we have determined the interfacial energy of the hydrate at 400 bars using the TIP4P/Ice and TraPPE molecular models for water and CO2, respectively, in combination with two different extensions of the Mold Integration technique [J. Colloid Interface Sci.

Simulation of the CO hydrate-water interfacial energy: The mold integration-guest methodology.

The growth pattern and nucleation rate of carbon dioxide hydrate critically depend on the precise value of the hydrate-water interfacial free energy. There exist in the literature only two independent experimental measurements of this thermodynamic magnitude: one obtained by Uchida et al. [J.

Density functional theory for the prediction of interfacial properties of molecular fluids within the SAFT-γ coarse-grained approach.

Recently, we have proposed the SAFT-VR Mie MF DFT approach [Algaba , , 2019, , 11937-11948] to investigate systems that exhibit fluid-fluid interfaces. This formalism is based on the combination of the Statistical Associating Fluid Theory for attractive potentials of variable range using Mie intermolecular potential (SAFT-VR Mie) and a Density Functional Theory (DFT) treatment of the free energy. A mean-field approach is used to evaluate the attractive term, neglecting the pair correlations associated to attractions.

Simulation of the carbon dioxide hydrate-water interfacial energy.

Hypothesis: Carbon dioxide hydrates are ice-like nonstoichiometric inclusion solid compounds with importance to global climate change, and gas transportation and storage. The thermodynamic and kinetic mechanisms that control carbon dioxide nucleation critically depend on hydrate-water interfacial free energy. Only two independent indirect experiments are available in the literature.

An accurate density functional theory for the vapor-liquid interface of chain molecules based on the statistical associating fluid theory for potentials of variable range for Mie chainlike fluids.

A new Helmholtz free energy density functional is presented to predict the vapor-liquid interface of chainlike molecules. The functional is based on the last version of the statistical associating fluid theory for potentials of variable range for homogeneous Mie chainlike fluids (SAFT-VR Mie). Following the standard formalism, the density functional theory (SAFT-VR Mie DFT) is constructed using a perturbative approach in which the free energy density contains a reference term to describe all the short-range interactions treated at the local level, and a perturbative contribution to account for the attractive perturbation which incorporates the long-range dispersive interactions.

Density functional theory for the description of spherical non-associating monomers in confined media using the SAFT-VR equation of state and weighted density approximations.

As a first step of an ongoing study of thermodynamic properties and adsorption of complex fluids in confined media, we present a new theoretical description for spherical monomers using the Statistical Associating Fluid Theory for potential of Variable Range (SAFT-VR) and a Non-Local Density Functional Theory (NLDFT) with Weighted Density Approximations (WDA). The well-known Modified Fundamental Measure Theory is used to describe the inhomogeneous hard-sphere contribution as a reference for the monomer and two WDA approaches are developed for the dispersive terms from the high-temperature Barker and Henderson perturbation expansion. The first approach extends the dispersive contributions using the scalar and vector weighted densities introduced in the Fundamental Measure Theory (FMT) and the second one uses a coarse-grained (CG) approach with a unique weighted density.

Extension of the Test-Area methodology for calculating solid-fluid interfacial tensions in cylindrical geometry.

We extend the well-known Test-Area methodology of Gloor et al. [J. Chem.

Simultaneous application of the gradient theory and Monte Carlo molecular simulation for the investigation of methane/water interfacial properties.

This work is dedicated to the simultaneous application of the gradient theory of fluid interfaces and Monte Carlo molecular simulations for the description of the interfacial behavior of the methane/water mixture. Macroscopic (interfacial tension, adsorption) and microscopic (density profiles, interfacial thickness) properties are investigated. The gradient theory is coupled in this work with the SAFT-VR Mie equation of state.

Interfacial properties of water/CO2: a comprehensive description through a Gradient Theory-SAFT-VR Mie approach.

The Gradient Theory of fluid interfaces is for the first time combined with the SAFT-VR Mie EOS to model the interfacial properties of the water/CO(2) mixture. As a preliminary test of the performance of the coupling between both theories, liquid-vapor interfacial properties of pure water have been determined. The complex temperature dependence of the surface tension of water can be accurately reproduced, and the interfacial thickness is in good agreement with experimental data and simulation results.

Interfacial properties of the Mie n-6 fluid: Molecular simulations and gradient theory results.

In a first part, interfacial properties of a pure monoatomic fluid interacting through the Mie n-6 potential (n=8, 10, 12, and 20) have been studied using extensive molecular simulations. Monte Carlo and molecular dynamics simulations have been employed, using, respectively, the test area approach and the mechanic route. In order to yield reference values, simulations have been performed with a cutoff radius equal to 10sigma, which is shown to be sufficient to avoid long range corrections.

Modeling of the linear viscoelastic properties of oil-in-water emulsions.

The aim of this work is to use a recently developed statistical model of dispersions with nonhydrodynamic interactions to describe the linear viscoelastic properties of emulsions of Newtonian liquids. None of the existing models can describe the rheological behavior of such systems, particularly the elastic properties, in the linear regime. We first present the results of numerical simulations of our model applied to emulsions.