Supersonically sprayed nanotextured surfaces with silver nanowires for enhanced pool boiling

•Silver nanowires (AgNW) were supersonically sprayed onto a copper substrate.•Silver nanowires were well connected because of self-sintering or fusion resulting from supersonic impacts.•The optimal thickness was identified that maximizes critical heat flux and the effective heat transfer coefficient.•The surface temperature of the heat source decreased substantially during efficient heat. Rapid production of nanoscale-textured surfaces for microscale devices is important for commercial applications. In this study, we introduce a commercially viable method to fabricate nanotextured surfaces used in pool-boiling heat-transfer applications. Silver nanowires were supersonically sprayed onto copper substrates with good adhesive strength. The coating method required little time and could be adapted for roll-to-roll processing. The fabricated nanotextured surfaces showed a significantly increased critical heat flux (CHF) and effective heat transfer coefficient (heff), as evidenced by the release of numerous bubbles from nanotextured nucleation sites during pool-boiling. The silver nanowires were well connected either by self-sintering or due to the fusion induced by supersonic impacts with the copper substrate. The thickness of the coated layer could be controlled by the number of spray sweeps/passes and the optimal thickness for maximizing CHF and heff was identified. The nanotextured surfaces were characterized by scanning electron microscopy and by bubble formation and release as visualized with a charge-coupled device camera.