Beetle-Inspired Anti-Frosting Surfaces

Research by Jonathan Boreyko

The Stenocara desert beetle has special hydrophilic bumps on its surface with which it can preferentially harvest water from the atmosphere and use it for drinking. Inspired by this, we have engineered surfaces with chemical micropatterns of contrasting hydrophobic and hydrophilic regions that serve as nucleation sites for condensation, due to the dramatically lower energy barrier for nucleation on the hydrophilic features. Such spatial control of condensation has remarkable applications in inter-droplet interfacial phenomena. One such application is the inhibition of frost growth.

Our group has previously shown that in-plane frost growth is an inter-droplet phenomenon, where frozen droplets harvest water from neighboring super-cooled liquid droplets to grow ice bridges that propagate across the surface in a chain reaction. In our experiments, we have discovered that when the separation between adjacent nucleation sites for supercooled condensate is properly controlled with chemical micropatterns prior to freezing, frost growth can be slowed and even halted entirely. To date no surface has been able to passively prevent the in-plane growth of frost across the population of supercooled condensate. Our group is presently working on such nature-inspired engineered surfaces with spatially controlled nucleation sites where by temporally controlling the onset of freezing events in-plane frost growth can be passively suppressed.

Development of beetle-inspired anti-frosting surfaces.