Validity of density functional theory to study drying transition

ABSTRACT

We explore the physical reason why some forms of density functional theory (DFT) cannot model drying phenomena. It is found that DFT of using perturbed functional with respect to single bulk density cannot account for the drying transition, due to the inadequate description of local physical property for the growing vapour layer. Then we propose a new method to solve the problem for this type of DFT. The free energy functional is decomposed as the summation of a local contribution of equation-of-state effect and a non-local contribution from the nature of long-range interaction. Results show that the DFT developed by this strategy predict well for the drying transition, and thus provides a reliable tool to study similar phase behaviour. This transformative theoretical method in DFT provides a new way to construct free energy functional that could correctly model the thermodynamics and phase behaviour in drying or wetting system.

Keywords:

• Density functional theory
• drying transition
• first-order mean spherical approximation
• perturbation method

Acknowledgments

We dedicate this paper to Dr. Yiping Tang in memory of his contribution in discovering FMSA.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant number 21404078]; the College Natural Science Foundation of Jiangsu [grant number KJD150008].