Static and dynamic contact angles of water droplet on a solid surface using molecular dynamics simulation

• Published in: Journal of colloid and interface science 2009-11, Vol.339 (1), p.187-195
• Main Authors: Hong, Seung Do, Ha, Man Yeong, Balachandar, S.
• Format: Article
• Language: English
• Subjects: Chemical Phenomena; Chemistry; Colloidal state and disperse state; Computer Simulation; Contact; Contact angle; Droplets; Dynamic tests; Dynamics; Exact sciences and technology; General and physical chemistry; Hydrophilic; Hydrophobic; Molecular dynamics; Molecular dynamics simulation; Simulation; Solid surfaces; Surface physical chemistry; Surface Properties; Water - chemistry; Water droplet
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2009.07.048

In order to observe the dynamic contact angle, we applied a body force in the positive x direction to a water droplet in equilibrium with the solid surface. The present study investigates the variation of static contact angle of a water droplet in equilibrium with a solid surface in the absence of a body force and the dynamic contact angles of water droplet moving on a solid surface for different characteristic energies using the molecular dynamics simulation. With increasing characteristic energy, the static contact angle in equilibrium with a solid surface in the absence of a body force decreases because the hydrophobic surface changes its characteristics to the hydrophilic surface. In order to consider the effect of moving water droplet on the dynamic contact angles, we apply the constant acceleration to an individual oxygen and hydrogen atom. In the presence of a body force, the water droplet changes its shape with larger advancing contact angle than the receding angle. The dynamic contact angles are compared with the static contact angle in order to see the effect of the presence of a body force.