Interfacial Entropy of Water on Rigid Hydrophobic Surfaces

Abstract

A simple theoretical model is proposed for computing the interfacial entropy of water at rigid hydrophobic surfaces. The interfacial entropy, which is not considered in mean field models of static wettability, is evaluated from the fluctuations of the water-surface dispersion energy at the single particle level and represents the configurational bias imposed on the fluid molecules by the attractive external potential of a solid wall. A comparison with results obtained from molecular dynamics simulations shows that the model quantitatively describes the entropy loss of water when a water-vapor interface turns to water in contact with hydrophobic surfaces such as graphene, graphite, and diamond, while it overestimates this quantity on hydrophilic surfaces.

Interfacial Tension Does Not Drive Asymmetric Nanoscale Electrowetting on Graphene

“…Therefore, differences in solvent structural organization on oppositely polarized surfaces, including differences in water hydrogen bonding interactions among the interfacial water molecules, do not affect Δγ SL . This conclusion underscores the analysis described in earlier work where it was demonstrated that variations in the liquid-liquid energy are exactly enthalpyentropy compensating in the work of adhesion [45][46]. The symmetric nature of Δγ SL is quite remarkable, in particular also in view of the fact that the water CA (Figure 3a) instead exhibits an asymmetric dependence on surface polarity.…”

Wettability Alteration and Enhanced Oil Recovery Induced by Proximal Adsorption of Na+ , Cl− , Liu1, Wani2, Alhassan3 et al. 2018Phys. Rev. Applied455270View full textAdd to dashboardCite

“…This method is particularly reliable using classical MD when one can use fairly large droplets. Here we use the work-ofadhesion approach [39][40][41][42][43], which we used successfully to investigate the water wettability of graphene [44] and hexagonal boron nitride [45] monolayers at the electronic structure level. We first give a brief description of the approach.…”

“…In pioneering studies with the work-of-adhesion approach, one first computes the work of adhesion of a water slab on a surface and then employs the Young-Dupré equation that relates the work of adhesion to the water contact angle (WCA) WCA [39][40][41][42][43]:…”

Water wettability of graphene: interplay between the interfacial water structure and the electronic structure

“…Theoretical calculations of WCAs of graphitic carbon surfaces have so far been done primarily using classical potentials, by constructing an analytical interaction potential between water and the solid surface based on interatomic Lennard-Jones potentials [19][20][21] or classical molecular dynamics (CMD) simulations. 19,[22][23][24][25][26][27][28][29] In those pioneering studies with the work-of-adhesion approach, one rst computes the work of adhesion of a water slab on a surface and then employs the Young-Dupré equation that relates the work of adhesion to the WCA. 19,[25][26][27][28] Alternatively, CMD can be sued to measures the shape of a water droplet on a surface and extract the WCA.…”

“…19,[22][23][24][25][26][27][28][29] In those pioneering studies with the work-of-adhesion approach, one rst computes the work of adhesion of a water slab on a surface and then employs the Young-Dupré equation that relates the work of adhesion to the WCA. 19,[25][26][27][28] Alternatively, CMD can be sued to measures the shape of a water droplet on a surface and extract the WCA. [22][23][24] Though these approaches have provided signicant insights into wetting behavior, 19,[22][23][24][25][26][27][28] they depend on the availability of reliable classical potentials.…”