Observation of Nucleate Boiling on a Fine Copper Wire with Superhydrophobic Micropatterns

Hydrophobic islands/patterns on a hydrophilic substrate could be employed to enhance boiling heat transfer, however the underlying mechanisms are far from clear. We perform boiling experiments on a copper wire coated with superhydrophobic micropatterns (contact angle >170°). The copper wire is as fine as 150 μm in diameter, greatly facilitating the observation of the bubble dynamic details. With the heat flux increasing, four regimes are characterized based on the bubble behavior. The superhydrophobic micropatterns are found to play critical roles in bubble formation and distribution as well as the interactions.