Control of tip nanostructure on superhydrophobic shape memory arrays toward reversibly adjusting water adhesion

In this paper, a fresh strategy for superhydrophobic surface adhesion control was advanced, which was demonstrated through tuning the pillar tip nanostructure on a shape memory polymer (SMP) substrate. The micro-/nanostructured pillars show low-adhesive superhydrophobicity. The nanostructure on pillar tips disappears after pressing by a flat silicon substrate and the surface becomes high-adhesive superhydrophobicity. The nanostructure reappears and the surface returns to the initial low-adhesive state with a further heating process. Invertible low/high adhesion switching can be realized by simply controlling the nanostructure on pillar tips, and the smart controllability can be explained by the polymer's shape memory effect (SME), based on which, different surface microstructure shapes and corresponding different solid/liquid contact states can be obtained. The work reports smart surface adhesion control through dynamically tuning the surface structure in the nanoscale on SMP. The results can provide a novel method for design of smart superhydrophobic surfaces and further improved the insight into the action of nanostructure on surface wetting/adhesion. A novel superhydrophobic surface with switchable adhesion is reported by creating micro-/nanostructured pillars on the shape memory polymer.