Ever notice how a dried coffee stain has a thicker outer
rim, while the middle of the stain remains almost unsoiled? This 'coffee ring
effect' also occurs in other materials. Researchers from the Departments of
Chemical Engineering and Chemistry at KU Leuven have now discovered how to
counteract coffee rings with 'surfactants', i.e. soap. The key to the discovery
was not a kitchen towel, but a bacterium that counteracts the coffee ring
effect at the microscopic level. The findings were published in a recent
edition of the leading journal Nature Communications.