Marangonieffecten

Marangoni effects, also known as the Marangoni phenomenon or the Gibbs-Marangoni effect, describe the transfer of mass or heat across an interface between two fluids due to surface tension gradients. These gradients can arise from variations in temperature or concentration of surface-active substances. When a surface tension gradient exists, the fluid is driven from regions of lower surface tension to regions of higher surface tension. This movement can lead to various observable phenomena.

In the context of heat transfer, if there is a temperature gradient at the interface, the surface tension will vary accordingly. Warmer regions typically have lower surface tension, causing the fluid to flow away from these areas towards cooler regions with higher surface tension. This flow can enhance heat transfer by transporting heat across the interface. A common example is the formation of "coffee rings" when a drop of liquid containing dissolved solids dries. As the edges of the drop dry faster, the surface tension increases, pulling liquid from the center to the edges, leaving a concentrated ring of solids.

In chemical processes and material science, Marangoni effects play a role in phenomena such as the formation of patterns in drying films, the behavior of bubbles and droplets, and the efficiency of certain coating processes. Understanding and controlling these effects is important for applications ranging from microfluidics and semiconductor manufacturing to food processing and the behavior of thin liquid films on solid surfaces. The direction and magnitude of the flow depend on the fluid properties, the nature of the interface, and the driving force (temperature or concentration gradients).