{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,12]],"date-time":"2026-03-12T04:20:36Z","timestamp":1773289236602,"version":"3.50.1"},"reference-count":37,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2013,9,6]],"date-time":"2013-09-06T00:00:00Z","timestamp":1378425600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/3.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Entropy"],"abstract":"<jats:p>A methodology for the determination of the solid-fluid contact angle, to be employed within molecular dynamics (MD) simulations, is developed and systematically applied. The calculation of the contact angle of a fluid drop on a given surface, averaged over an equilibrated MD trajectory, is divided in three main steps: (i) the determination of the fluid molecules that constitute the interface, (ii) the treatment of the interfacial molecules as a point cloud data set to define a geometric surface, using surface meshing techniques to compute the surface normals from the mesh, (iii) the collection and averaging of the interface normals collected from the post-processing of the MD trajectory.  The average vector thus found is used to calculate the Cassie contact angle (i.e., the arccosine of the averaged normal z-component). As an example we explore the effect of the size of a drop of water on the observed solid-fluid contact angle. A single coarse-grained bead representing two water molecules and parameterized using the SAFT-\u03b3 Mie equation of state (EoS) is employed, meanwhile the solid surfaces are mimicked using integrated potentials. The contact angle is seen to be a strong function of the system size for small nano-droplets. The thermodynamic limit, corresponding to the infinite size (macroscopic) drop is only truly recovered when using an excess of half a million water coarse-grained beads and\/or a drop radius of over 26 nm.<\/jats:p>","DOI":"10.3390\/e15093734","type":"journal-article","created":{"date-parts":[[2013,9,6]],"date-time":"2013-09-06T12:09:54Z","timestamp":1378469394000},"page":"3734-3745","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":76,"title":["On the Calculation of Solid-Fluid Contact Angles from Molecular Dynamics"],"prefix":"10.3390","volume":"15","author":[{"given":"Erik","family":"Santiso","sequence":"first","affiliation":[{"name":"Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK"},{"name":"Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA"}]},{"given":"Carmelo","family":"Herdes","sequence":"additional","affiliation":[{"name":"Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK"}]},{"given":"Erich","family":"M\u00fcller","sequence":"additional","affiliation":[{"name":"Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK"}]}],"member":"1968","published-online":{"date-parts":[[2013,9,6]]},"reference":[{"key":"ref_1","unstructured":"Mattia, D. 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