Superhydrophobic shape memory film with switchable adhesion to both water and solid

Abstract

• The membrane can regulate the adhesion to both solid and water droplets. • Both microstructure and surface energy were crucial for special adhesion. • The membrane can be used to in-situ capture/release both solid and liquid. Recently, inspired by gecko’s smart adhesion, many intelligent adhesive surfaces have been reported. However, all of these are focused on single adhesion to liquid or solid, to obtain a surface with switchable adhesion to both water and solid is still a challenge. Herein, by coating a layer of polyurethane (PU) with micropillar structures onto a shape memory polymer (SMP) substrate to imitate the skin and muscle of the gecko’s foot, respectively, we report a new shape memory film that can repeatedly display curved/unfolded shapes with the help of the excellent shape memory property. Research results indicate that besides the variation of the contact area, a proper surface energy is also crucial for the special adhesion. Furthermore, based on the smart adhesive performance, in-situ capture/release of both solid and liquid were demonstrated by using the film. This research proposes a film with tunable adhesion to both solid and liquid, which provides a fresh idea for designing novel adhesive film, and meanwhile broadens the application of the adhesive materials.