Synthesis and characterization of superhydrophobic–superoleophilic surface

The binary superhydrophobic–superhydrophilic surface has been successfully achieved by a combination of nanoscale texture roughness on micro-textured cotton thread network by layer-by-layer deposition method through the single-step sol–gel route. Furthermore, microstructures with improved wettability were produced, in which silica nanotextures were grown without modifying the chemical method to form superoleophilic and superhydrophobic networks. A superoleophilic surface (oil contact angle 0°) and a superhydrophobic coated cotton fabric with surface free energy of γ ^total = 13. 23 ± 0.37 mJ m⁻² (water contact angle of 167 ± 1° and a small sliding angle of 4 ± 1°) were successfully obtained. The results were exemplified here by the creation of immiscible oils separation membranes, and the innumerable applications of this technology also include self-cleaning fabrics, antistaining fabrics, water purification, and antiwetting fabrics for military applications.