Repetitive Pool Boiling Runs: A Controlled Process to Form Reduced Graphene Oxide Surfaces from Graphene Oxide with Tunable Surface Chemistry and Morphology

Wettability and wickability of a surface are the key properties that govern a variety of industrial applications. Understanding the effect of aging on the durability of these surfaces and subsequent changes occurring in their molecular structure is vital to maintain functionality. In this work, we used repetitive pool boiling to test the durability of graphene oxide-copper (GO-Cu) coated surfaces and studied subsequent changes in surface chemistry and morphology. We observed the transformation of GO-Cu to reduced GO-copper (rGO-Cu) coating that led to improved boiling performance. This improvement is attributed to (a) transition of hydrophilic GO to hydrophobic rGO due to the repetitive pool boiling, (b) increased surface roughness as a result of hydrophobic surfaces, and c) increased surface inhomogeneity due to the presence of three elements- carbon, oxygen and copper. The durability of the GO-Cu coatings was found to be higher than pristine-copper and just-copper coated surfaces. A higher performance demonstrated by GO-Cu coatings indicates its increased sustainability and practicability in numerous engineering applications.