Marangoniflöden

Marangoniflöden, also known as Marangoni flows, are fluid motions driven by gradients in surface tension along an interface. The phenomenon was first described by Italian physicist Carlo Marangoni in the 19th century, and it has since become a fundamental concept in fluid dynamics and surface science.

When a liquid surface experiences a spatial variation in temperature or concentration of a surfactant, the local surface tension changes. Regions of lower surface tension tend to attract fluid from areas of higher surface tension, producing a tangential stress that generates flow. This surface‑tension‑driven movement is distinct from bulk pressure‑driven flows and can occur even in the absence of external forces such as gravity or applied pressure gradients.

Marangoni flows can be observed in a variety of contexts, including the spreading of liquid metal on a substrate, the self‑propulsion of droplets on liquid surfaces, and the transport of contaminants on water. In microfluidic devices, controlled Marangoni stresses enable precise pumping and mixing without moving parts. The phenomenon also plays a critical role in coatings, painting and the marine industry, where temperature differences across a film or surfactant gradients can influence coating uniformity and boat hull performance.

In material science, Marangoni convection is exploited in crystal growth and thin‑film deposition to achieve homogeneous structures. In biology, similar surface‑tension gradients guide mucus transport in airway epithelia and the movement of epithelial cells during wound healing. Because Marangoni flows can be both beneficial and deleterious, researchers continue to develop methods to monitor, predict, and manipulate surface‑tension gradients in engineering and natural systems.