Physicists discover why drying liquid crystal drops leave unusual ‘coffee rings’

In previous papers, University of Pennsylvania physicists investigated the “coffee ring effect,” the ring-shaped stain of particles left after drops of coffee evaporate. In one paper, they learned how to undo this effect by altering particle shape. Now, in a new paper published in Nature Communications, they have uncovered the complex and remarkably different behavior arising in a liquid crystal drop that is drying.