In　this　work,　a　simple　immersion　technique　was　created　to　further　enhance　the　pool　boiling　heat　transfer　performance　of　micro-nano　copper　foam　by　modifying　its　mixed　wettability.　The　SEM　images　exhibit　that　the　entirely-covered　micro/nanostructures　can　be　observed　on　the　super-hydrophilic　copper　foam,　while　the　hydrophilic-hydrophobic　copper　foam　is　covered　with　nanograss　partially.　The　experiments　indicated　that　the　hydrophilic-hydrophobic　copper　foam　showed　the　best　heat　transfer　coefficient　of　the　all　sample　surfaces　at　a　high　heat　flux　(＞40　W/cm2),　which　can　be　as　high　as　4.15　W/cm2·K.　Meanwhile,　the　critical　heat　flux　(CHF)　was　measured　as　108.32　W/cm2,　which　was　157.3%　higher　than　that　on　the　smooth　surface,　and　57%,　33.2%　and　37.4%　higher　than　that　of　untreated,　super-hydrophilic,　super-hydrophobic　copper　foams,　respectively.　Interestingly,　due　to　the　unique　modification　of　the　surface,　the　onset　of　boiling　(ONB)　on　the　sample　was　much　reduced　from　9　K　to　0.5　K.　These　improvements　are　due　to　the　increasing　nucleation　density,　the　reduced　bubble　departure　diameter　and　the　much　shortened　bubble　period　compared　to　other　comparative　samples.　It　is　speculated　that　enhancement　of　the　boiling　heat　transfer　is　attributed　to　the　synergistic　effect　of　improved　bubble　nucleation,　the　vapor　escape,　and　the　liquid　replenishment　on　the　designed　sample　with　a　mix　wettability.　©　2023