Gecko toe pads inspired in situ switchable superhydrophobic shape memory adhesive film.

Nanoscale

MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China.

Published: May 2019

Recently, smart adhesive superhydrophobic surfaces have attracted much attention. However, it is still a challenge to obtain a superhydrophobic surface with shape memory adhesive performance. Herein, inspired by the special back-scrolling/unfolding ability of gecko toe pads and corresponding tunable adhesion, we report such a film produced by sticking a layer of superhydrophobic pillar structured polyurethane (s-PU) onto a shape memory polyurethane-cellulose nanofiber (PU-CNF) substrate to mimic the hair-like skin structure and underlying muscle of the gecko toe pads, respectively. Similar to the muscle of the gecko toe pads, the excellent shape memory effect of the PU-CNF substrate can help the obtained film to memorize and repeatedly display different shapes and solid/water contact models. Thus reversible switching between multiple states from the low-adhesive rolling performance to the high-adhesive pinning performance can be realized. Meanwhile, based on its smart wetting performance, not only the traditional in situ capture/release of one microdroplet, but also the step-by-step release of different droplets can be realized on our film. This work reports a new superhydrophobic shape memory adhesive film, which offers a novel strategy for surface adhesion control and meanwhile opens a new road for applications in controlled droplet manipulation.

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Source
http://dx.doi.org/10.1039/c9nr00154aDOI Listing

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