Evaporated whiskey inspires coating technology

PRINCETON, N.J., March 25 (UPI) -- A team of researchers at Princeton University recently poured out perfectly good whiskey and let it evaporate. The loss wasn't a total waste, however, as it may ultimately lead to a new type of industrial coating.

The experiment was inspired by the curiosity of photographer Ernie Button who noticed the last few drops of whiskey, when left in a clear glass, left behind unique residues. When lit from beneath using different colored lights, the whiskey glass and patterned residues made for dramatic photography.

Button asked his physicist pal what was going on, and before he knew it, his friend set up an experiment at Princeton.

The first thing the team of scientists noticed was that whiskey doesn't leave behind a "coffee ring" when it evaporates. The outer edges of a coffee spill evaporate more quickly, changing the surface tension and pulling more coffee to the outer edge.

The reason evaporated whiskey doesn't leave behind a ring is because the liquor features fat-like molecules that keep surface tension to a minimum. As a result, as whiskey evaporates from the edge, liquid is pulled back into the middle.

Additionally, whiskey has a high concentration of plant-derived polymers that keep the liquid molecules stuck to the counter, glass or table.

Researchers confirmed their findings by making whiskey-like liquids and then taking away their lipid molecules or polymers. When they did, the liquids evaporated like coffee.

Scientists say their findings, published in the journal Physical Review Letters, could inspire new technologies like industrial coatings or 3D printer ink.