Surface wettability and contact angle analysis by dissipative particle dynamics

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 <TEX>55∘</TEX> to <TEX>165∘</TEX> predicted by the normalized parameter (<TEX>|ASL|/BSL</TEX>) were reported. Droplet with the parameters <TEX>|ASL|</TEX><TEX>&</TEX><TEX>gt;5.84BSL0.297</TEX> was found to be hydrophilic. If <TEX>|ASL|</TEX> was much smaller than <TEX>5.84BSL0.297</TEX>, the droplet was found to be superhydrophobic.