Reversible transition between adhesive and antiadhesive performances by stretching/recovery on superhydrophobic TPU/CNTs composite membrane surface

Reversible and facile transition between adhesive and antiadhesive performances on superhydrophobic surface is desired but still challenging. In this work, a composite membrane has been fabricated by filtering multi-walled carbon nanotubes (MWCNTs) suspensions on thermoplastic polyurethane (TPU) nonwovens. This surface exhibits superhydrophobic properties because of the hierarchical roughness. The water droplet adhesion behaviors on the surface depend crucially on the stretching or recovery state of the composite membranes. Upon stretching, the groove among fibers is so wide that more and more hydrophilic defects (TPU fibers) have been exposed to water droplets, resulting in the adhesive surface with higher sliding angle; on the contrary, the CNTs network covers the whole membrane after recovery, leading to the Cassie state and antiadhesive performance with enhanced mobility of droplet on the surface. Our result opens a new avenue for tailoring the water droplets adhesion behaviors on superhydrophobic surface.