Interfacial profiles in fluid/liquid systems: A description based on the storing of elastic energy

An analytical expression for the interfacial energy is found by solving a Poisson equation and assuming a Boltzmann distribution of volume elements forming the fluid/liquid system. Interfacial phenomena are treated as a result of the response of a liquid when it makes contact with other fluid phase, in order to reach thermal and mechanical equilibrium. This model gives a quantitative description of the interface, obtaining values for its molar, force and energy density profiles. Also, our model allows the determination of the proportion of the fluids present in the interfacial zone, the values of interfacial tension and thickness. In the case of water + n-alkanes systems, the tensions are in agreement with the behavior shown by the experimental data. Finally, the values for interfacial thickness predicted from molar density profiles are lower than the range of influence of the elastic energy and elastic field.

Fluid/liquid interface schematic representation: (a) Two sub-phases are formed adjacent to the contact plane by the effect of the surface scalar potential φ and (b) in response to this potential each i-subphase has a proper stored energy density Ui(z) ( Similar fluids, different fluids).Figure optionsDownload high-quality image (43 K)Download as PowerPoint slideFigure optionsDownload high-quality image (<1 K)Download as PowerPoint slideFigure optionsDownload high-quality image (<1 K)Download as PowerPoint slideResearch highlights
► An analytical expression for the elastic interfacial energy is proposed.
► The interfacial phenomena are considered as a response of a liquid in contact with other fluid phase.
► This model describes the molar, force and energy density profiles of the interface.
► The interfacial tension and thickness has been estimated.
► Our results for water + n-alkanes, are agree to the experimental behaviour.