Solution‐processed Graphene Oxide Coatings for Enhanced Heat Transfer During Dropwise Condensation of Steam

Abstract Hydrophobic coatings have the ability to promote dropwise condensation on metal surfaces. In this work, reduced graphene oxide coatings are fabricated by dip coating copper substrates into a graphene oxide colloidal suspension, followed by thermal reduction. The formation of reduced graphene oxide is demonstrated by Raman and X‐ray photoelectron spectroscopy characterizations, while scanning electron microscopy, atomic force microscopy and dynamic water contact angle analyses are employed to verify the morphology and the wettability of the coatings. The prepared coatings demonstrate applicability in the promotion of dropwise condensation of pure steam, with an 8‐fold enhancement of the heat transfer coefficient compared to film‐wise condensation. In addition, durability of the reduced graphene oxide coatings of more than 100 hours in the tested condition is reported.