Tunable Bubble Assembling on a Hybrid Superhydrophobic-Superhydrophilic Surface Fabricated by Selective Laser...

Inspired by water striders walking on water, aluminum alloy plates with patterned superhydrophobic (SH) surfaces made by picosecond laser texturing and stearic acid treatment were enabled floating with load on water. Self-assembling of shape tunable air bubbles was achieved on the designated surface with hybrid SH/superhydrophilic (SHL) patterns that fabricated by the second selective laser texturing of the prepared SH plate. Different load-bearing capacities were obtained by changing the position and area of SH surfaces, and an outstanding weight loading capacity of 7.5 g on a 20 cm² aluminum alloy plate (3750 g/m², 1.34 times the self-weight) was gained with strip-shaped air bubbles adhered to the sample bottom surface. The drag reduction characteristics of SH/SHL surfaces with different shaped air bubbles were tested by a self-built single pendulum impact device; the results indicated that the sample with the whole exterior SH surface achieved the longest sailing distance, which is 26.7% increase than that of the untreated bare sample. The research implies a promising strategy to increase the load-bearing capacity and voyage of marine vehicles by manipulating the underwater solid/air/liquid interaction on biomimic functional surfaces.