Hybrid graphene oxide/crumpled graphene film via subcooled boiling-induced self-assembly for highly efficient boiling heat transfer

Graphene-based films generated on a substrate can modify surface structure and chemistry to enable the improvement in heat transfer capacity for many important boiling-related applications. Current methods for preparing these films, however, require additional processing equipment and involve relatively complex processes. Achieving simple and controllable generation of these films remains a great challenge. In this work, we develop a facile subcooled boiling-induced self-assembly (SBISA) method for generating graphene-based films. We first explore the SBISA mechanism and demonstrate the formation of graphene-based films under the action of a combined force induced by the capillary pressure, structural disjoining pressure, and vapor recoil force. In addition, using the SBISA process, we generate a tunable hybrid graphene oxide (GO)/crumpled graphene (CG) film with mixed wettability. The hybrid GO/CG film enables large performance enhancements for boiling with a 150.0% increase in the critical heat flux (CHF) and a 163.9% increase in the maximum heat transfer coefficient (HTC) over a pristine copper surface. This SBISA strategy provides an alternative approach for fabricating tunable films with a hierarchical structure and mixed wettability on various substrates, and it may also help produce surfaces with different micro/nanostructures for enhancing phase-change-based heat transfer. (C) 2021 The Author(s). Published by Elsevier Ltd.