Super-spreading on superamphiphilic micro-organized nanochannel anodic aluminum oxide surfaces for heat dissipation

Nature-inspired superamphiphilic surfaces have drawn tremendous attention owing to its extreme liquid-loving behaviors. Herein, a micro-organized nano-channel (Mo-Na) superamphiphilic anodic aluminum oxide (AAO) surface with long-lasting superamphiphilic property is prepared by a facile one-step anodization method with controllable temperature change. Analysis of dynamic wetting behaviors on superamphiphilic Mo-Na AAO surfaces for various liquids reveals that the spreading factor is in negative correlation with the surface tension and liquid polarity. Detailed observation of the three-phase contact line shows a micro-scale capillary film on superamphiphilic Mo-Na AAO surfaces, which results from the horizontal component of the capillary force. Taking advantage of the superamphiphilic property, water droplets can spread completely on these Mo-Na AAO surfaces within a short time, which can be applied for efficient heat dissipation. Moreover, the unique AAO surface with Mo-Na structures also offers an effective template for future efforts in AAO-based composite devices.