October_AMP_Digital

A D V A N C E D M A T E R I A L S & P R O C E S S E S | O C T O B E R 2 0 2 0 9 labs. Both groups observed the same trend—the MOFs become more insulat- ed when filled with adsorbates. Their findings were also validated by atom- istic simulations at University of Pitts- burgh in collaboration with Carnegie Mellon University. pitt.edu . 3D-PRINTED AEROGELS Researchers from Empa, Switzer- land, are producing stable, well-shaped microstructures from silica aerogel by using a 3D printer. The printed struc- tures can be as thin as a tenth of a millimeter. The new aerogel has even better mechanical properties and can even be drilled and milled. This opens up completely new possibilities for the post-processing of 3D-printed aerogel moldings. With the new patent-pending method, it is possible to precisely ad- just the flow and solidification prop- erties of the silica ink from which the aerogel is later produced, so that both self-supporting structures and wa- fer-thin membranes can be printed. As an example of overhanging structures, the researchers printed leaves and blossoms of a lotus flower. The test object floats on the water surface due to the hydrophobic properties and low density of the silica aerogel—just like its natural model. The new technolo- gy also makes it possible for the first time to print complex 3D multi-material microstructures. With such structures it is now com- paratively trivial to thermally insulate even the smallest electronic compo- nents from each other. The researchers also constructed a “thermos-molecu- lar” gas, or Knudsen, pump. When it is placed under a light source, it becomes warm on the dark side and starts to pump gases or solvent vapors. But it can do more than just pump. If the air is contaminated with an environmen- tal toxin, the air can circulate through the membrane several times and the pollutant is chemically broken down by a reaction catalyzed by the manganese oxide nanoparticles. Such sun-pow- ered, autocatalytic solutions are partic- ularly appealing in the field of air anal- ysis and purification on a very small scale due to their simplicity and dura- bility. www.empa.ch. Researchers 3D-printed this lotus flower made of aerogel.