Buckling of drying droplets of colloidal suspensions
Authors: N. Tsapis, E. R. Dufresne, S. S. Sinha, C. S. Riera, J.W. Hutchinson, L. Mahadevan, and D. A. Weitz
Physical Review Letters 94, 018302 (2005)
Soft matter keywords
buckling, elastic shell, drying, sol-gel, Leidenfrost effect
By Tom Kodger
Abstract from the original paper
Minute concentrations of suspended particles can dramatically alter the behavior of a drying droplet. After a period of isotropic shrinkage, similar to droplets of a pure liquid, these droplets suddenly buckle like an elastic shell. While linear elasticity is able to describe the morphology of the buckled droplets, it fails to predict the onset of buckling. Instead, we find that buckling is coincident with a stress-induced fluid to solid transition in a shell of particles at a droplet’s surface, occurring when attractive capillary forces overcome stabilizing electrostatic forces between particles.