Thin Jet Flies Two for One: Double streams yield sheathed nanoballs, fibers
By Peter Weiss
Powerful electric fields can stretch liquids into narrow jets that burst into sprays of droplets. This phenomenon has revolutionized mass spectrometry, a technique for weighing a sample’s constituent atoms and molecules. Meanwhile, some industries are testing the technique, known as electrospray, for such uses as making and delivering drugs.
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Researchers in Spain and the United States have now applied electrospray principles in a novel way, creating ultrathin liquid jets in which a stream of one liquid encloses a stream of another. When such a coaxial jet breaks up, it produces exceptionally tiny, coated droplets. Or, if the coaxial flow is allowed to quickly solidify, the technique yields coated fibers.