Pressure gradients fail to predict diffusio-osmosis. (25th April 2018)

• Record Type: Journal Article
• Authors: Liu, Yawei; Ganti, Raman; Frenkel, Daan
• Is Part Of: Journal of physics. Volume 30:Number 20(2018)
• Publication Date: 2018-04-25
• Subjects: interfacial flows -- diffusio-osmosis -- molecular dynamics; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/aabd58
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: We present numerical simulations of diffusio-osmotic flow, i.e. the fluid flow generated by a concentration gradient along a solid-fluid interface. In our study, we compare a number of distinct approaches that have been proposed for computing such flows and compare them with a reference calculation based on direct, non-equilibrium molecular dynamics simulations. As alternatives, we consider schemes that compute diffusio-osmotic flow from the gradient of the chemical potentials of the constituent species and from the gradient of the component of the pressure tensor parallel to the interface. We find that the approach based on treating chemical potential gradients as external forces acting on various species agrees with the direct simulations, thereby supporting the approach of Marbach et al (2017 J. Chem. Phys .146 194701). In contrast, an approach based on computing the gradients of the microscopic pressure tensor does not reproduce the direct non-equilibrium results.