Direct Laser-Induced Graphene Patterning on Metals with Tunable Surface Wettability for Thermal Management and Anti-Icing Applications

Laser-induced graphene (LIG) synthesis is typically confined to polymer substrates, which suffer from suboptimal electrical and thermal conductivities and limit LIG’s applications in scenarios requiring robust thermal and mechanical performance. Besides, control over LIG’s morphology during fabrication is meticulous, hindering the precise tailoring of its surface properties across a wide range for practical utilizations. To tackle these challenges, a simple scaling law was proposed in this study to estimate the laser energy density needed to completely transform a polyimide film laminated on metallic substrates to LIG on metallic substrates. Our results demonstrated successful LIG synthesis on various metals, with the LIG–metal interface exhibiting a significantly reduced out-of-plane electrical resistance to less than 10 Ω, a substantial enhancement over conventional LIG-polymer systems. The LIG–metal configurations displayed an over 5-fold increase in out-of-plane thermal conductivity compared to their polymer-based counterparts, alongside exceptional mechanical and thermal stability, withstanding high-temperature exposures up to 500 °C with minimal wettability alterations (<4%) and maintaining LIG structural integrity across 250 cycles of adhesive tape peel test. We also developed a multiple laser scribing strategy to decouple the energy input for LIG–metal interface formation and LIG surface morphology reconstruction. By manipulating the intersecting angle between laser scans, we achieved precise area control over hydrophobic and hydrophilic LIG domains, continuously adjusting the overall contact angles from >130° (hydrophobic) to ∼0° (superhydrophilic). These findings broaden LIG’s applicability in diverse fields such as interfacial thermal material for thermal management and anti-icing coating for metal surfaces.