Anomalous boiling of saline water in graphene nanoconfinement

The phenomena of boiling at the nanoscale exhibit unique behavior compared to the bulk owing to the inception of an electrical double layer (EDL) near the charged walls resulting in a non-trivial influence on the phase-change dynamics. We probe the impact of surface-mediated interactions on nanoscale boiling of water confined between graphene surfaces, using a systematic set of molecular dynamics simulations. Our study delineates an intricate interplay of substrate temperature, salt concentration, and graphene surface charge on boiling characteristics of confined aqueous NaCl solutions, which can be inherently linked with variations in EDL thickness. We report enhanced heat transfer efficiency over an optimized range of conditions induced by the favorable orientation of interfacial water molecules and hydrogen bonding network. The study demonstrates the oddities associated with the largely underexplored nanoscale boiling of aqueous solution confined with graphene surfaces, not only providing effective pathways towards maximizing the heat transfer efficiency in two-dimensional (2D) materials but also carries immense implications in a plethora of applications ranging from electro-thermal applications, particularly in microfluidics and actuation technologies.