Oscillating Chiral-Nematic Fingerprints Wipe Away Dust

This work presents an approach to create mechanical undulations at a solid organic coating surface under the influence of an electric field. The coating is fabricated through polymerization of chiral reactive mesogens aligned in their fingerprint mode on top of interdigitated electrodes. The fingerprint mode gives a corrugation of the surface perpendicular to the helix axes. When a lateral alternating electric field is applied, the order parameter of the helicoidally packed mesogens is reduced. This simultaneously leads to an inversion of the fingerprint heights, an overall thickness increase, and a chaotic and fast surface oscillation. These three effects work in concert stimulating wavy deformation figures at the coating surface. The process is fast and reversible; the dynamics of the topographic textures stop immediately when the electric field is switched off. The continuous generation of surface undulations sustains transport of species at the coating surface. It removes dust and debris providing an active dust control.