Fabrication of super-repellent cotton textiles with rapid reversible wettability switching of diverse liquids

By in situ introducing polyaniline (PANI) and perfluorooctanoic acid (PFOA) to cotton fibers, normally hydrophilic and oleophilic cotton textile has easily turned superhydrophobic and highly oleophobic. This super-repellent cotton fabric exhibits a high contact angle (>150°) and low contact angle hysteresis, even with liquids possessing significantly low surface tension. The water or oil repellent property is ascribed to the combination of a dual-size surface roughness and low-surface-energy material. In particular, a reversible wettability switching of various low-surface-tension liquids on the PANI-fabric can be simultaneously observed, when it is doped with PFOA and de-doped with sodium hydroxide via a simple dipping method. This transition can be explained by the conversion of fluorine content and hydrophilic groups on the surface during the doping/dedoping process. Besides, this doping polymerization and dedoping process can slightly affect the mechanical strength of the cotton fabrics, even with harsh chemicals like acid and base.