Selective Alignment of Molecular Glass Wrinkles by Engineered Magnetic Field Landscapes

A new approach for aligning wrinkles in thin viscoelastic polymethylmethacrylate films is established by sandwiching them between ferromagnetic layers. Experiments prove that a contribution from an engineered anisotropic 1D periodic magnetic stray field pattern can be decisive for the alignment of otherwise randomly oriented wrinkles at commensurate periods of the magnetic template pattern and the wrinkles. Alternatively, random wrinkling is observed under similar conditions, but when periodic magnetic stray fields are missing or not commensurate with the wrinkle wavelength. The possibility to stabilize two distinct types of wrinkling patterns in the same material system paves the way toward mechanically reconfigurable functional elements, enabling exciting possibilities for stretchable electronics, magnetic field sensors, and tuneable gratings for optoelectronics and photonics.