Self-healing atypical liquid-infused surfaces: Superhydrophobicity and superoleophobicity in submerged conditions

Self-healing atypical liquid-infused surfaces (ALIS) which demonstrate very high bubble/drop angles (>160°) and ultra-low contact angle hysteresis (CAH <2°) have been facilely fabricated. Porous hydrophilic nano-filtration membrane was submerged in water to form water-infused surface and hydrophobic stretched polytetrafluoroethylene film in decane to form alkane-infused surface. The air bubble/liquid drop (2 µL) can move with ease on ALIS in submerged conditions at a low tilted angle of 2°. The rolling motion of a water drop is observed, similar to its motion on a superhydrophobic surface. Surfactant addition into the water drop intensifies CAH of superhydrophobic surfaces but has negligible effects on wetting properties of ALIS. In the presence of surfactant, the fluid particle moves readily on ALIS, but its velocity exhibits a non-monotonic variation with surfactant concentrations due to surface remobilization. Mechanically damaged ALIS demonstrate the self-healing ability of its wetting properties and preserve the particle motion even at a low inclination of 2°. This study provides the simple principle for developing liquid-infused surfaces with ultra-low CAH and self-healing ability under submerged conditions, which can be used for designing droplet-based devices.