Nanoid Canyons On-Demand: Electrically Switchable Surface Topography in Liquid Crystal Networks.

Topography is a key factor that governs important properties of surfaces, such as adhesion and wettability, and materials with switchable surface topographies will have switchable surface properties. We demonstrate a principle to generate electrically switchable surface topographies on the surface of a thin nematic liquid crystal elastomer film which is sandwiched between a continuous electrode and a random metal network. Voltage-controlled displacement of the metal network toward the continuous electrode is achieved, resulting in unprecedented topographical modulations in the range of 0-2.5 μm. We show that this depth variation is significantly larger than the expected deformation because of electrostatic attraction between the network and the continuous electrode. This effect is explained by deformation due to the rotation of the liquid crystal side groups along the electric field lines.