| Full text | |
| Author(s): |
Almeida, Alexandre B.
;
Buldyrev, Sergey, V
;
Alencar, Adriano M.
;
Giovambattista, Nicolas
Total Authors: 4
|
| Document type: | Journal article |
| Source: | Journal of Physical Chemistry C; v. 125, n. 9, p. 14-pg., 2021-03-02. |
| Abstract | |
We perform molecular dynamics (MD) simulations of nanoscale water capillary bridges (WCBs) expanding between two parallel walls and determine the smallest separation between the walls above which the capillarity theory (CT) remains valid. We consider silica-based walls with tuned surface partial charges that expand from hydrophobic to hydrophilic. We find that the CT is valid (i.e., it predicts successfully the WCB geometry and forces induced on the walls) for, approximately, wall separations h >= h(0) = 3.0 nm for all surfaces considered. At these separations, the CT holds without including any line tension and the results are robust relative to the method employed to obtain the WCB profile from MD simulations. At approximately 2.0 nm <= h < h(0), the contact angle of water theta varies with h, suggesting that at such wall separations the CT requires the inclusion of a line tension tau However, we find that the specific behavior of theta(h) and the associated value of t are inherently dependent on the method employed to calculate the WCB profile from MD simulations. Interestingly, the forces induced by the WCBs on the walls obey the prediction of the CT without the need to include a line tension for approximately h >= 2.5 nm for all surfaces considered. Our results are interpreted in terms of the rearrangement of water molecules within the WCBs and show that the CT breaks down at h < h(0) because its assumptions, that the WCB is a bulklike water volume confined by solid-liquid and liquid-vapor interfaces, do not hold. (AU) | |
| FAPESP's process: | 17/11631-2 - CINE: computational materials design based on atomistic simulations, meso-scale, multi-physics, and artificial intelligence for energy applications |
| Grantee: | Juarez Lopes Ferreira da Silva |
| Support Opportunities: | Research Grants - Research Centers in Engineering Program |