Mesh can rest on dandelion without disturbing the seeds, is lighter than a feather
Mankind has long been trailing nature in quality of materials. A feather's intricate structural design lends it a density of 0.0025 g/cm3 [source]. By contrast, man has been forced to rely on much denser materials like Styrofoam, which has a density of ~0.02 g/cm3 [source].
But mankind has at last one-upped nature, producing a metal thin-film mesh, which has a density of 0.0009 g/cm3 -- about a third the density of feathers. It can rest gently atop a bed of dandelion fluff without damaging the bloom.
The material was invented by researchers at the University of California, Irvine; HRL Laboratories (a commercial partner); and the California Institute of Technology.
William Carter, manager of the architected materials group at HRL and the senior author of the paper on the work, says the material draws inspiration from human macroscopic structural engineering triumphs, stating, "Modern buildings, exemplified by the Eiffel Tower or the Golden Gate Bridge, are incredibly light and weight-efficient by virtue of their architecture. We are revolutionizing lightweight materials by bringing this concept to the nano and micro scales."
To build the incredible nanomesh, the researchers first made a polymer mesh using a self-propagating photopolymer waveguide technique. Thiol-ene was the selected class of photopolymers (thiol-enes are four-branched hyrocarbon molecules with a central junction of silicon and a sulfur connector midway on each branch).
An electroless nickel plating technique was then applied. When you want to coat a solid object in metal, one common way is to use electricity to force metal atoms to stick to the surface. Another method relies on a chemical reaction to plate. In this case the reaction is between hydrated phosphates and nickel, which is auto-catalyzing.
The end result is a 100 nm thick layer of NiP, that's 7% phosphorous and 93% nickel by weight. The layer is solid, and is a (supersaturated) solution of phosphorous.
The photoplastic is then eaten away using etching techniques. What is left behind is essential tubes made out of smaller tube "beams". This tubes out of tubes approach yields a substance that's surprisingly strong, but is also 99.99 percent air.