to self-assemble nanoparticles into ordered arrays and to grow ordered nanotubes. An alcohol containing nanoparticles is spread on the substrate, followed by blowing humid air over the substrate. The alcohol is evaporated under the flow. Simultaneously, water condenses and forms microdroplets on the substrate. Meanwhile, the nanoparticles in alcohol are transferred into the microdroplets and finally form numerous coffee rings on the substrate after drying. Another application is the manipulation of particles taking advantage of the relevance of the surface tension effects at small scales. A controlled thermo-capillary convection is created by locally heating the air–water interface using an infrared laser. Then, this flow is used to control floating objects in both position and orientation and can prompt the self-assembly of floating objects, profiting from the Cheerios effect. The Marangoni effect is also important to the fields of welding, crystal growth and electron beam melting of metals. See also Plateau–Rayleigh instability — an instability in a stream of liquid Diffusioosmosis - the Marangoni effect is flow at a fluid/fluid interface due to a gradient in the interfacial free energy, the analog at a fluid/solid interface is diffusioosmosis References External links Motoring Oil Drops Physical Review Focus February 22, 2005 Thin Film Physics, ISS astronaut Don Pettit demonstrate. YouTube-movie. Fluid mechanics Convection Physical phenomena Articles containing video clips