Self-Moving blooming drops of dimethyl sulfoxide containing benzyne intermediate for solutal transport

Abstract

Drop motion can be achieved on surfaces with low to negligible contact angle hysteresis. The droplets can be made to move under the influence of an external force or droplets can show self-propelled motion. The studies on drop motion are crucial for the design and application of surfaces for controlling drop motion. In this work, self-propelled motion of non-aqueous drops containing an active solute on a total wetting glass surface is reported. The benzyne intermediate 2(-Trimethylsilyl) phenyltrifluoromethane sulfonate (TPS) in DMSO (dimethyl sulphoxide) and octadecylamine in hexadecane were used as active components of binary/ternary drops showing self-induced motion. When drops of these were casted on high-temperature treated glass surface, random drop motion was observed followed by complete spreading of the drop. In case of DMSO, the drop periphery expanded with time while forming a rim, a central spherical cap inside the spreading drop was formed that shows random motion. This behaviour of drop was referred as a confused spreading-blooming drop, as spreading of DMSO drop occurs with rim formation outside and a self-moving drop formed inside the casted area. The unique non-aqueous drop spreading was evaluated by varying the solutal concentrations. This work depicts the unique combination of surface and drops showing potential application in self-propelled drop motion.