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.

Artificial Mushroom Sponge Structure for Highly Efficient and Inexpensive Cold-Water Steam Generation.

A bioinspired structure of an artificial mushroom, made of the common polyvinyl alcohol sponge coated with charcoal, is fabricated, with high efficiency in generating cold water steam of ≈73% under 1 sun illumination, due to very high light absorption, efficient water supply, and low heat loss. In addition, the structure is very inexpensive, and thus ideal for applications in portable cold (boil-free) steam generators for water purification and desalination.

Erratum: Artificial Mushroom Sponge Structure for Highly Efficient and Inexpensive Cold-Water Steam Generation.

[This corrects the article DOI: 10.1002/gch2.201800035.].