Dynamic density functional theory for drying colloidal suspensions: Comparison of hard-sphere free-energy functionals

Abstract

Dynamic density functional theory (DDFT) is a promising approach for predicting the structural evolution of a drying suspension containing one or more types of colloidal particles. The assumed free-energy functional is a key component of DDFT that dictates the thermodynamics of the model and, in turn, the density flux due to a concentration gradient. In this work, we compare several commonly used free-energy functionals for drying hard-sphere suspensions including local-density approximations based on the ideal-gas, virial, and Boublík-Mansoori-Carnahan-Starling-Leland (BMCSL) equations of state as well as a weighted-density approximation based on fundamental measure theory (FMT). To determine the accuracy of each functional, we model one- and two-component hard-sphere suspensions in a drying film with varied initial heights and compositions, and we compare the DDFT-predicted volume-fraction profiles to particle-based Brownian dynamics (BD) simulations. FMT accurately predicts the structure of the one-component suspensions even at high concentrations and when significant density gradients develop, but the virial and BMCSL equations of state provide reasonable approximations for smaller concentrations at a reduced computational cost. In the two-component suspensions, FMT and BMCSL are similar to each other but modestly overpredict the extent of stratification by size compared to BD simulations. This work provides helpful guidance for selecting thermodynamic models for soft materials in nonequilibrium processes such as solvent drying, solvent freezing, and sedimentation.

References in corpus (35)

• Is Random Close Packing of Spheres Well Defined?
• Dynamic Density Functional Theory of Fluids
• Dynamical density functional theory and its application to spinodal decomposition
• Classical dynamical density functional theory: from fundamentals to applications
• Density functional theory for hard-sphere mixtures: the White-Bear version Mark II
• Dynamic stratification in drying films of colloidal mixtures
• Non-equilibrium sedimentation of colloids on the particle scale
• Cross-interaction drives stratification in drying film of binary colloidal mixtures
• Power functional theory for Brownian dynamics
• Diffusiophoresis in non-adsorbing polymer solutions: the Asakura-Oosawa model and stratification in drying films
• Generalized dynamical density functional theory for classical fluids and the significance of inertia and hydrodynamic interactions
• Dynamical density functional theory with hydrodynamic interactions and colloids in unstable traps
• Power functional theory for many-body dynamics
• A reversible mesoscopic model of diffusion in liquids: from giant fluctuations to Fick's law
• An Efficient Algorithm for Classical Density Functional Theory in Three Dimensions: Ionic Solutions
• Dynamical density functional theory: binary phase-separating colloidal fluid in a cavity
• Molecular Dynamics Simulations of Evaporation-Induced Nanoparticle Assembly
• Dynamic Density Functional Theory with hydrodynamic interactions and fluctuations
• Phase coexistence of active Brownian particles
• Stratification of mixtures in evaporating liquid films occurs only for a range of volume fractions of the smaller component
• Superadiabatic forces in Brownian many-body dynamics
• The overdamped limit of dynamic density functional theory: Rigorous results
• Influence of hydrodynamic interactions on stratification in drying mixtures
• Quantized bounding volume hierarchies for neighbor search in molecular simulations on graphics processing units
• Flow and structure in nonequilibrium Brownian many-body systems
• Stratification of drying particle suspensions: Comparison of implicit and explicit solvent simulations
• Diffusion and sedimentation in colloidal suspensions using multiparticle collision dynamics with a discrete particle model
• Capillary Forces on a Small Particle at a Liquid-Vapor Interface: Theory and Simulation
• Dynamical density functional theory for the drying and stratification of binary colloidal dispersions
• Dynamics of localized particles from density functional theory
• Stratification of polymer mixtures in drying droplets: hydrodynamics and diffusion
• Particle Conservation in Dynamical Density Functional Theory
• Order-preserving dynamics in one dimension -- single-file diffusion and caging from the perspective of dynamical density functional theory
• Particle-conserving dynamics on the single-particle level
• Directional freezing of binary colloidal suspensions: A model for size fractionation of graphene oxide

Cited by in corpus (7)

• Perspective: How to overcome dynamical density functional theory
• Perspective: New directions in dynamical density functional theory
• Exploring the role of hydrodynamic interactions in spherically-confined drying colloidal suspensions
• Sedimentation path theory for mass-polydisperse colloidal systems
• Stability of nanoparticle laden aerosol liquid droplets
• Classical density functional theory for nanoparticle-laden droplets
• Inverse design of drying-induced assembly of multicomponent colloidal-particle films using surrogate models