Femtosecond laser-based construction of 3D spatially distributed graphene oxide surface for enhancing boiling heat transfer

To address the difficulties of ultrahigh heat flux transfer in energy and ultra-high heat dissipation applications, pool boiling has been utilized in various extreme heat transfer fields owing to the benefits of high heat flux dissipation. Although graphene-based planar nanocoating with superior in-plane thermal conductivity are employed to enhance heat transfer performance in pool boiling, further improvement of boiling characteristics remains challenging due to the limited and difficult-to-control optimizable factors, such as nanoroughness and wettability. In this work, utilizing a femtosecond laser, a copper substrate with a three-dimensional microstructure topography has been predesigned and fabricated to construct three-dimensional spatially distributed graphene oxide nanocoating surface (3DSD-GO) as a new heat enhancement-optimization strategy in order to obtain a new heat transfer enhancement factor. 3DSD-GO introduces adaptive heat conduction–regional liquid supply mechanism that can adaptively adjust the heat dissipation mode according to the heat distribution of boiling surface to achieve the synergy enhancement of convective heat transfer and phase-change heat transfer. Therefore, 3DSD-GO delays the trigger of the critical heat flux while ensuring the improvement of heat transfer coefficient during nucleate boiling. Additionality, owing to the flexibility of femtosecond laser, GO nanocoating can be formed at a variety of microstructures having different topography and obtain different 3DSD-GO to improve heat transfer performance. Overall, the findings in this work provide a remarkable insight toward breaking the heat transfer limit of graphene-based nanocoating and can be applied in extreme heat transfer fields.