Light-driven Locomotion of Underwater Bubbles on Ultrarobust Paraffin-impregnated Laser-ablated Fe₃O₄-doped Slippery Surfaces

Manipulating underwater bubbles (UGBs) is realized on morphology-tailored or stimuli-responsive slippery lubricant-impregnated porous surface (SLIPS). Unfortunately, the volatile lubricants (e. g., silicone oil, ferrofluid) greatly decrease their using longevity. Designed is light-responsive paraffin-infused Fe3O4-doped slippery surface (LR-PISS) by incorporation of hybrid lubricants and superhydrophobic micropillar-arrayed elastometric membranes resulted from one-step femtosecond laser vertically scanning. Upon LR-PISS, the dynamic motion control bwteen pinning and sliding along free routes over UGB could be realized by alternately loading/discharging NIR-trigger. The underlying principle is that when the NIR was applied, UGB would be actuated to slide along the NIR trace because the irradiated domain melts for a slippery surface within 1.0 s. Once the NIR is removed, the liquefied paraffin would be reconfigured to solid phase for pinning a moving UGB within 0.5 s. Newly explored hydrokinetics imparts us with capability of steering UGBs to arrange any desirable patterns and switch light-path behaving as the light-control-light optical shutter. In comparison with previously reported SLIPS, current LR-PISS unfolds unparalleled ultrarobust antidisturbance ability even in flowing liquid ambient. More significantly, even subjected to physical damage, underwater LR-PISS is capable of in situ self-healing within 13 s under the assistance of remote NIR. The results here could inspire the design of robust bubble manipulator and further boost their applications in optofluidics and all-optical modulators.