Prediction of Contact Angles and Density Profiles of Sessile Droplets Using Classical Density Functional Theory Based on the PCP-SAFT Equation of State

Sauer, Elmar; Terzis, Alexandros; Theiss, Marc; Groß, Joachim

doi:10.1021/acs.langmuir.8b01985

Cited by 30 publications

(15 citation statements)

References 95 publications

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“…Therefore, the parameters published are predestined but not restricted to usage in studies of interfacial phenomena. This includes the adsorption in porous media , and nucleation phenomena for which water and alcohols are prevalent components in studies. , …”

Section: Discussionmentioning

confidence: 99%

Multiobjective Optimization of PCP-SAFT Parameters for Water and Alcohols Using Surface Tension Data

Rehner

Groß

2020

J. Chem. Eng. Data

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With predictive methods, such as classical density functional theory and predictive density gradient theory (pDGT), it is possible to model bulk phase properties and interfacial tensions using the same model. For nonassociating fluids, these models can be used to predict interfacial properties for systems that lack experimental data. For associating components, however, predictions often show large deviations to experiments, which is at least partially rooted in highly correlated pure component parameters. Therefore, we use interfacial properties for discriminating pure component parameters by amending the PCP-SAFT parameter estimation for water and alcohols by including surface tension data in the objective function. To obtain a comprehensive comparison between different association models, a multiobjective optimization is performed. By analyzing the resulting pareto fronts, it is shown that including a fitted dipole moment improves the results for water but not for alcohols. The result of the multiobjective optimization is inconclusive about the optimal choice of association scheme for water as the preferred model changes along the pareto front. For small alcohols, in contrast to chemical intuition, the 4C association scheme gives the best results. For longer alcohols, the pareto analysis shows the limits of the homosegmented modeling approach.

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Section: Discussionmentioning

confidence: 99%

Multiobjective Optimization of PCP-SAFT Parameters for Water and Alcohols Using Surface Tension Data

Rehner

Groß

2020

J. Chem. Eng. Data

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“…Sauer and Gross extended PC-SAFT to inhomogeneous system using a weighted density approach 35 . The Helmholtz energy functional was successfully applied to the prediction of contact angles 36 , adsorption isotherms 37 and the calculation of Tolman lengths 38 .…”

Section: Introductionmentioning

confidence: 99%

Predicting solvation free energies in non-polar solvents using classical density functional theory based on the PC-SAFT equation of state

Eller

Matzerath

Westen

et al. 2021

The Journal of Chemical Physics

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We propose a predictive Density Functional Theory (DFT) for the calculation of solvation free energies. Our approach is based on a Helmholtz free-energy functional that is consistent with the perturbed-chain SAFT (PC-SAFT) equation of state. This allows a coarse-grained description of the solvent, based on an inhomogeneous density of PC-SAFT segments. The solute, on the other hand, is described in full detail by atomistic Lennard-Jones interaction sites. The approach is entirely predictive, as it only takes the PC-SAFT parameters of the solvent and the force-field parameters of the solute as input. No adjustable parameters or empirical corrections are involved. The framework is applied to study self-solvation of n-alkanes and to the calculation of residual chemical potentials in binary solvent mixtures. Our DFT approach accurately predicts solvation free energies of small molecular solutes in three different solvents. Additionally, we show the calculated solvation free energies agree well with those obtained by molecular dynamics simulations and with the residual chemical potential calculated by the bulk PC-SAFT equation of state. We observe higher deviations for the solvation free energy of systems with significant solute-solvent Coulomb interactions.

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“…20 The modeling of inhomogeneities, according to Shi et al, can be approached by a "top-down" approach, where model parameters are adjusted to macroscopic experimental properties such as adsorption isotherms or contact angles. Sauer and Gross 21 Ravikovitch, and Thommes proposed a quenched-solid DFT, 22,23 where the solid is represented by a spatially varying density profile to effectively incorporate surface roughness in a one-dimensional approach. The solid−fluid interactions are accounted for by an additional contribution to the Helmholtz energy functional instead of an external potential.…”

Section: ■ Introductionmentioning

confidence: 99%

“…The modeling of inhomogeneities, according to Shi et al, can be approached by a “top-down” approach, where model parameters are adjusted to macroscopic experimental properties such as adsorption isotherms or contact angles. Sauer and Gross fitted solid–fluid interaction parameters to experimental contact angle measurements of n -octane on a Teflon surface to predict contact angles of other substances. Neimark, Ravikovitch, and Thommes proposed a quenched-solid DFT, , where the solid is represented by a spatially varying density profile to effectively incorporate surface roughness in a one-dimensional approach.…”

Section: Introductionmentioning

confidence: 99%

Free-Energy-Averaged Potentials for Adsorption in Heterogeneous Slit Pores Using PC-SAFT Classical Density Functional Theory

Eller

Groß

2021

Langmuir

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This study analyzes the adsorption behavior in two-dimensional heterogeneous slit pores using nonlocal density functional theory based on the perturbed-chain statistical associating fluid theory (PC-SAFT) equation of state. Both chemical heterogeneity and surface roughness on small atomistic scales are investigated. The solid structure is considered as individual solid interaction sites whereby chemical heterogeneity is introduced through the presence of different solid–fluid sites and molecular roughness by varying the position of the interaction sites in the first solid layers. The effect of both forms of heterogeneity on the adsorption behavior is assessed individually. Effective one-dimensional solid–fluid potentials provide a way to reduce the dimensionality and computational demand of the density functional theory (DFT) calculations. We determine one-dimensional free-energy-averaged (FEA) solid–fluid potentials of methane and n-butane in the low-density limit for solid systems with molecular roughness and chemical heterogeneity. Using this effective one-dimensional solid–fluid potential at any density, we find excellent agreement of adsorption isotherms for both solid descriptions in systems with homogeneous slit pores. Subcritical adsorption isotherms of n-butane in slit pores with surface roughness show deviations at higher pressures due to the formation of fluid layers in the one-dimensional FEA potential. Chemical heterogeneity introduces a shift of the capillary condensation pressure below the saturation pressure of the bulk liquid, which is well described by the free-energy-averaged system.

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Prediction of Contact Angles and Density Profiles of Sessile Droplets Using Classical Density Functional Theory Based on the PCP-SAFT Equation of State

Cited by 30 publications

References 95 publications

Multiobjective Optimization of PCP-SAFT Parameters for Water and Alcohols Using Surface Tension Data

Multiobjective Optimization of PCP-SAFT Parameters for Water and Alcohols Using Surface Tension Data

Predicting solvation free energies in non-polar solvents using classical density functional theory based on the PC-SAFT equation of state

Free-Energy-Averaged Potentials for Adsorption in Heterogeneous Slit Pores Using PC-SAFT Classical Density Functional Theory

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