Long-term super-amphiphilic shaped-fiber with multi-scale grooved structures: toward spontaneous self-cleaning

Despite long-term exposure to the ambient environment, fabrics made of bamboo fibers enable spontaneous self-cleaning of oil contaminants without using any surfactant. Here, it is revealed that the long-term stable super-amphiphilicity of bamboo fibers is responsible for self-cleaning behavior. Liquids of both water and oil are liable to super-spread on bamboo fibers, driven by multi-scaled capillary forces imparted by the unique shaped fibrous structures with multi-scale hierarchical ridges/grooves. Based on the minimization of free energy, the pre-wetted oils can be easily removed away by forming the water film, reaching the spontaneous self-cleaning. Notably, the super-amphiphilicity induced by the structure shows better long-term stability compared with that endowed by chemical modification. It is demonstrated that the bio-inspired artificial counterpart also exhibits excellent self-cleaning property, which inspires innovative self-cleaning textures.