Reversibly Switchable Topography Enabled by Melting and Crystallization of Melt-Electrowritten Polymer Fibers

We report the fabrication of topographically structured surfaces with reversibly switchable topography by using melt electrowriting (MEW). In particular, MEW was used to produce continuous high aspect ratio lamellae of semicrystalline polyester urethane with a poly(1,10-decylene adipate) soft segment. The switching of topography is achieved by the expansion and contraction of the polymer caused by the melting and crystallization of the soft segment that results in the buckling of lamellae. In the molten stage, lamellae can be buckled in a certain direction by capillary forces caused by water droplets between two lamellae. In addition, the interlamellar distance between neighbors’ lamellae can be managed by water droplets. Finally, we have demonstrated the possibility of creating electrically conductive surfaces with switchable conductivity achieved by the reversible buckling of the lamellae.