Meniscus lithography and Moiré patterns

Meniscus lithography and Moiré patterns. Bottom-up pattern formation at the micro- and nanoscale is being actively studied for a better understanding of self-organization and for such applications as data storage and sensors. One low-energy approach relies on the evaporation of liquids to produce patterns of nanoparticles across multiple length scales. In one variation, the local rate of evaporation can be controlled by placing a mask over the liquid. Additionally, capillary forces not only form menisci between the particles but can also organize the particles into patterned clusters. Random imperfections and instabilities, though, make achieving long-range order difficult. In a new approach, Joanna Aizenberg and colleagues at Harvard University have found a simple, scalable way for masked evaporation to produce complex patterns and long-range order. The researchers place two arrays of vertical nanopillars—one the substrate and one the mask—face to face with a liquid sandwiched between them. In an example of...