Surface wettability and contact angle analysis by dissipative particle dynamics

Abstract

A dissipative particle dynamics (DPD) simulation was presented to analyze surface wettability and contact angles of a droplet on a solid platform. The many-body DPD, capable of modeling vapor-liquid coexistence, was used to resolve the vapor-liquid interface of a droplet. We found a constant density inside a droplet with a transition along the droplet boundary where the density decreased rapidly. The contact angle of a droplet was extracted from the isosurfaces of the density generated by the marching cube and a spline interpolation of 2D cutting planes of the isosurfaces. A wide range of contact angles from 55 o to 165 o predicted by the normalized parameter (|ASL|/BSL) were reported. Droplet with the parameters |ASL| > 5.84BSL 0.297 was found to be hydrophilic. If |ASL| was much smaller than 5.84BSL 0.297 , the droplet was found to be superhydrophobic.