NMR imaging of falling water drops - art. no. 144501

The falling water drop is a simple model for studying phenomena related to chemical extraction, where two immiscible phases are dynamically blended to promote the transport of solute molecules from one phase to the other. Con vective motion inside the drop significantly influences the extraction effi ciency. Whereas optical and tracer methods are model bound or invasive, NMR imaging is noninvasive, direct, and applicable to nontransparent media. Th e first NMR measurements of a water drop falling through air are reported. It is shown that, in drops from pure water, large-scale convection tolls ar e observed in contrast to drops with the surface tension lowered by surfact ants.