"Penn Science Cafe The Coffee Ring Effect: Silly-Sounding Research Goes a Long Way
As anyone who has ever spilled coffee knows, liquids that contain suspended particles tend to leave ring-shaped stains when they dry. Physicists have known what causes this ""coffee-ring effect"" for some time, but recent research by Peter Yunker, a graduate student in the Department of Physics and Astronomy in the School of Arts and Sciences at Penn, showed how simply changing the particles' shape could prevent the effect. Though it sounds silly, this discovery has major implications in the many printing and manufacturing processes where even coatings are necessary. His paper, co-authored by Arjun Yodh, the director of Penn's Laboratory for Research on the Structure of Matter, was recently featured on the cover of Nature, one of the world's top scientific journals.
