[SY-O2] Symposium O-2

[SY-O2] Droplet Spreading on a Surface Exhibiting Solid-liquid Interfacial Premelting

^○Yang Yang¹, Brian B Laird² (1.East China Normal University, China, 2.University of Kansas, United States of America)

We study the spreading kinetics of Pb(l) droplets on an Al(111) substrate using MD simulation. The Al-Pb solid-liquid interface was found [Phys. Rev. Lett, 110, 096102 (2013)] to exhibit premelting below the T_m(Al). Because the Al(111) free surface does not premelt, the spreading of the droplet is accompanied by a transition from a faceted to a premelted surface. We examine the effect of this premelting on the droplet spreading kinetics and compare the results to two standard mechanisms of droplet spreading: hydrodynamic spreading, in which energy dissipates through viscous relaxation, and kinetic spreading, where friction dominates. When premelting is present, kinetic spreading is observed at intermediate times, with exponential relaxation at long times. For two non-premelting Al/Pb interfaces (one faceted surface at 625K and one where premelting was suppressed) hydrodynamic spreading is seen instead at intermediate times. We also examine the effect of premelting on the droplet equilibrium contact angle.