Under-Oil Switchable Superhydrophobicity to Superhydrophilicity Transition on TiO₂ Nanotube Arrays

Abstract

Recently, smart interfacial materials that can reversibly transit between the superhydrophobicity and superhydrophilicity have aroused much attention. However, all present performances happen in air, and to realize such a smart transition in complex environments, such as oil, is still a challenge. Herein, TiO nanotube arrays with switchable transition between the superhydrophobicity and superhydrophilicity in oil are reported. The switching can be observed by alternation of UV irradiation and heating process, and the smart controllability can be ascribed to the cooperative effect between the surface nanostructures and the chemical composition variation. By using the controllable wetting performances, some applications such as under-oil droplet-based microreaction and water-removal from oil were demonstrated on our surface. This paper reports a surface with smart water wettability in oil, which could start some fresh ideas for wetting control on interfacial materials.

In situ growth of hierarchical Al2O3 nanostructures onto TiO2 nanofibers surface: super-hydrophilicity, efficient oil/water separation and dye-removal

“…Nevertheless, conventional ceramic materials with high surface energy exhibit low repellence for both water and oil droplets [8], and thus failed in selectively separation for immiscible oil/water mixture which is governed by interfacial phenomenon [9]. Although lots of materials with tunable surface wettability have been reported by controlling surface chemical composition and microstructure alone, or together [10][11][12][13], templatefree ceramic nanofibrous membrane with super surface wettability is still rarely reported. This is possibly due to the difficulties in tuning the surface wettability for a chemicaland physical-stable materials.…”

Rapid Fabrication of Superhydrophilic Micro/Nanostructured Nickel Foam Toward High‐Performance Glucose Sensor

“…The second is the superhydrophilicity. [ 55–57 ] The contact angle test results demonstrate that the formed NiO on the surface of the laser‐treated Ni foam sample interacts with the water through the hydrogen bond, enhancing the mass transfer of glucose, since the whole experimental processes were carried out in aqueous solution. The third is the good conductivity of laser‐treated Ni foam.…”

Bioinspired Designs of Superhydrophobic and Superhydrophilic Materials

“… 73 Recently, superhydrophilic/-hydrophobic fabric with self-propelled directional wetting patterns controlled by UV illumination and temperature has been successfully created by a one-step coating process involving nano-TiO 2 . 74 Random frameworks can also be generated by chemical methods such as etching/oxidation, layer-by-layer, sol–gel methods, and so on. Zhu et al 75 reported a simple three-step treatment method to generate superamphiphilic silicon wafer surfaces with contact angles near 0° for both water and typical organic liquids.…”