Unidirectional droplet motion onrncrosswise-striped surface

摘要

The behaviour of a droplet settled on an energetically heterogeneous surface is studied by simulation and simplifiedrnanalytical methods. The surface energy inhomogeneities are represented by a pattern of a series of parallel stripesrnof monotonically increasing width and two different contact angles. The isotropic random forces acting on therndroplet induce a highly asymmetric movement of the droplet. The observed shift of the droplet is perpendicular tornthe stripes and directed towards decreasing width of the stripes. The system behavior described as a series ofrndroplet positions and morphologies in local stationary states is studied by means of simulations with a finiteelementrnmethod performed by the Surface Evolver program. The influence of chosen system parameters on therndroplet trajectory is considered, including the details of the surface pattern, the fluctuation temperature, the surfacernand line tensions. The influence of model parameters on the trajectory of the droplet is discussed. A simplernanalytical model explaining the droplet translocation is proposed.