To avoid those annoying coffee-rings on your table, try switching to whiskey!
This is Sandra Tsing Loh with the Loh Down on Science, saying:
Slow down. This study comes to us via engineers Hyoungsoo Kim and Howard Stone at Princeton University. They were inspired by photographer Ernie Button’s portraits of whiskey droplets.
Depending on the liquid, droplets dry differently and leave behind unique films. Kim and Stone wanted to find what liquids make more uniform coatings.
They found that those coffee-rings happen because water dries faster on the edge than in the middle. Water rushes to the edge to replenish this loss. The result is the famous coffee-ring effect. You’re left cleaning up a stain before you’ve finished your morning cup of Joe.
But whiskey droplets dry randomly and stay in place when they contact a surface. The difference between coffee and whiskey? Whiskey contains alcohol and fats. Coffee doesn't.
So, the researchers made different blends of alcohol, water, fat, and particles. They figured out what makes whiskey better at producing uniform films.
This will be really helpful for 3D printers that build upon each layer as ink dries.
So when it comes to making uniform coatings, forget Joe. Stick to your new best friends—Johnny, Jack, and Jim!