Condensation on superhydrophobic copper oxide nanostructures

Abstract

Condensation is an important process in many power generation and water desalination technologies. Superhydrophobic nanostructured surfaces have unique condensation properties that may enhance heat transfer through a mechanism driven by surface tension. The increased droplet removal rate and reduced size of departing droplets facilitates improvements over traditional filmwise and dropwise condensation. This work investigates copper oxide nanostructures as a potential substrate for superhydrophobic condensation. We first explored and refined a procedure for creating and functionalizing oxide nanostructures on copper surfaces. The condensation behavior of these samples was characterized using an optical microscope and an environmental scanning electron microscope by quantifying the distribution of nucleation sites and droplet growth behavior. Using the knowledge gained from these studies, an experimental test bed was designed and fabricated to measure macro-scale condensation heat transfer for flat and tubular sample geometries. Preliminary results validate previous theoretical and experimental studies of filinwise condensation and demonstrate heat transfer enhancement with dropwise condensation. The copper oxide nanostructures exhibited jumping, which shows the effectiveness of the synthesis procedure.