Imperial College London
Alternate

ProfessorSerafimKalliadasis

Faculty of Engineering, Department of Chemical Engineering

Prof in Engineering Science & Applied Mathematics
 
 
 
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Contact

 

+44 (0)20 7594 1373s.kalliadasis Website

 
 
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Assistant

 

Miss Jessica Baldock +44 (0)20 7594 5699

 
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Location

 

516ACE ExtensionSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Ravipati:2018:10.1063/1.5021088,
author = {Ravipati, S and Aymard, B and Kalliadasis, S and Galindo, A},
doi = {10.1063/1.5021088},
journal = {Journal of Chemical Physics},
title = {On the equilibrium contact angle of sessile liquid drops from molecular dynamics},
url = {http://dx.doi.org/10.1063/1.5021088},
volume = {148},
year = {2018}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - We present a new methodology to estimate the contact angles of sessile drops from molec-ular simulations, by using the Gaussian convolution method of Willard and Chandler (J.Phys.  Chem.  B, Vol.  114, 1954-1958, 2010) to calculate the coarse-grained density fromatomic coordinates.   The iso-density contour with average coarse-grained density valueequal to half of the bulk liquid density is identified as the average liquid-vapor (LV) inter-face. Angles between the unit normal vectors to the average LV interface and unit normalvector to the solid surface, as a function of the distance normal to the solid surface, arecalculated.  The cosines of these angles are extrapolated to the three-phase contact line toestimate the sessile drop contact angle.  The proposed methodology,  which is relativelyeasy to implement,  is systematically applied to three systems:  (i) a Lennard-Jones (LJ)drop on a featureless LJ9-3surface; (ii) an SPC/E water drop on a featureless LJ9-3sur-face; and (iii) an SPC/E water drop on a graphite surface. The sessile drop contact anglesestimated with our methodology for the first two systems, are shown to be in good agree-ment with the angles predicted from Young’s equation.  The interfacial tensions requiredfor this equation are computed by employing the test-area perturbation method for the cor-responding planar interfaces.  Our findings suggest that the widely adopted spherical-capapproximation should be used with caution, as it could take a long time for a sessile dropto relax to a spherical shape, of the order of100ns, especially for water molecules initiatedin a lattice configuration on a solid surface. But even though a water drop can take a longtime to reach the spherical shape, we find that the contact angle is well established muchfaster and the drop evolves towards the spherical shape following a constant-contact-anglerelaxation dynamics.  Making use of this observation, our methodology allows a good es-timation of the sessile drop
AU  - Ravipati,S
AU  - Aymard,B
AU  - Kalliadasis,S
AU  - Galindo,A
DO  - 10.1063/1.5021088
PY  - 2018///
SN  - 0021-9606
TI  - On the equilibrium contact angle of sessile liquid drops from molecular dynamics
T2  - Journal of Chemical Physics
UR  - http://dx.doi.org/10.1063/1.5021088
UR  - http://hdl.handle.net/10044/1/58618
VL  - 148
ER  -
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