(460e) Transformation of GO Surfaces to Reduced-GO Surfaces with Tunable Surface Chemistry and Morphology Via Pool Boiling Process

Owing to supreme thermal conductivity and wetting properties, graphene coatings have been exploited in numerous two-phase heat transfer applications such as electronics cooling, reboilers, refrigeration, and desalination. Boiling is a heat transfer process accompanied by phase change from liquid to vapor, subsequently, pool boiling involves the boiling of a stagnant liquid over a heated surface. For various manifestations, the pool boiling performance of a surface is dictated by higher critical heat fluxes and heat transfer coefficients. This talk will focus on use of repetitive pool boiling as a tool to test the durability of graphene oxide-copper (GO-Cu) coated surfaces and the subsequent transformation of GO-Cu to reduced GO-copper (rGO-Cu) coating that further led to improved boiling performance. This improvement is attributed to a) transition of hydrophilic GO to hydrophobic rGO due to the repetitive pool boiling, and b) increased surface roughness because of hydrophobic surfaces. 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.