Subcooled flow boiling heat transfer in a microchannel with chemically patterned surfaces

•Wettability patterned surface can achieve higher HTC than homogeneous hydrophilic surfaces for subcooled flow boiling in a microchannel.•Patterns can control the nucleation sites and confine the bubble shapes in flow boiling.•Wettability patterned surface can improve the bubble mobility in comparison with homogeneous surface.•Mass flux affects the subcooled flow boiling heat transfer performance in a patterned microchannel.