Drops, liquid layers and the Marangoni effect

An overview is given of recent results about the onset and development of steady and time–dependent flow motions past an instability threshold induced by the Marangoni effect. First, I consider the case of a liquid drop immersed in another immiscible liquid when (endo– or exothermic) reaction, heat and/or mass transfer at/across the drop surface, etc., leads to self–propelled drop motion, overcoming viscous drag. Then I recall salient features about the spreading of an immiscible or a dissolving drop (with surfactant) on the surface of another liquid. Finally, I consider Bénard layers when either steady convective patterns or waves are produced by appropriate heat or mass transfer across the open surface.