journal article

Journal Article

Text

The Journal of Chemical Physics, 155(6), p. 064703-1-064703-15

Water on hydroxylated silica surfaces: Work of adhesion, interfacial entropy, and droplet wetting

AIP Publishing

English

Text

https://doi.org/10.1063/5.0056718

Bistafa Carlos, Surblys Donatas, Kusudo Hiroki, et al. Water on hydroxylated silica surfaces: Work of adhesion, interfacial entropy, and droplet wetting. The Journal of Chemical Physics, 155(6), 064703 (2021) https://doi.org/10.1063/5.0056718.

In the last few years, much attention has been devoted to the control of the wettability properties of surfaces modified with functional groups. Molecular dynamics (MD) simulation is one of the powerful tools for microscopic analysis providing visual images and mean geometrical shapes of the contact line, e.g., of nanoscale droplets on solid surfaces, while profound understanding of wetting demands quantitative evaluation of the solid–liquid (SL) interfacial tension. In the present work, we examined the wetting of water on neutral and regular hydroxylated silica surfaces with five different area densities of OH groups 𝜌^<oh>_<𝐴>, anging from a non-hydroxylated surface to a fully hydroxylated one through two theoretical methods: thermodynamic integration (TI) and MD simulations of quasi-two-dimensional equilibrium droplets. For the former, the work of adhesion needed to quasi-statically strip the water film off the solid surface was computed by the phantom wall TI scheme to evaluate the SL interfacial free energy, whereas for the latter, the apparent contact angle θ_app was calculated from the droplet density distribution. The theoretical contact angle θ_YD and the apparent one θ_app, both indicating the enhancement of wettability by an increase in 𝜌^<oh>_<𝐴>, presented good quantitative agreement, especially for non-hydroxylated and highly hydroxylated surfaces. On partially hydroxylated surfaces, in which θ_YD and θ_app slightly deviated, the Brownian motion of the droplet was suppressed, possibly due to the pinning of the contact line around the hydroxyl groups. Relations between work of adhesion, interfacial energy, and entropy loss were also analyzed, and their influence on the wettability was discussed.

© 2021 Author(s). This article is licensed under a Creative Commons Attribution 4.0 International License.

83318

Water on hydroxylated silica surfaces: Work of adhesion, interfacial entropy, and droplet wetting

AIP Publishing

English

The Journal of Chemical Physics

155

6

064703-1

064703-15

https://doi.org/10.1063/5.0056718

https://hdl.handle.net/11094/83318