Partial coalescence of sessile drops with different liquids*

We examine numerically the interaction between two deformable drops consisting of two perfectly miscible liquids sitting on a solid substrate under a given contact angle. Driven by solutal Marangoni forces, several distinct coalescence regimes are achieved after the droplets collision [1]. Phase diagrams for different control parameters are emphasized, which give predictions about drop behavior along the solid substrates, control of various interfacial effects, manipulations of tiny droplets in micro- and nano-fluidic devices without power supply, design of droplets or cleaning surfaces.\\[4pt] [1] R. Borcia, M. Bestehorn, {\it{Langmuir}} {\bf{29}} (2013) 4426; {\it{Fluid Dynamics Research}} {\bf{46}} (2014) 041405.