Figure 1: Synthesis of colored alginate aerogel beads: manual production by dropwise adding alginate solution to a CaCl2 coagulation bath (left) and up scaling of synthesis with the help of a Jet Cutter (middle and right) (Copyright: DLR)
Every year on Girl’s Day more than one hundred girls from various schools visit the German Aerospace Centre (Deutsches Zentrum für Luft- und Raumfahrt, DLR), to gain an insight into their technical and scientific world of work. This special day shall raise interest for girls in the STEM subjects (science, technology, engineering and mathematics) to improve the share of women in the so-called „all-male professions“ and to counteract the shortage of skilled workers in these fields.
Divided into several groups, the girls got to know the different institutes and departments of DLR. Four groups of 2-7 girls each had the possibility of getting to know the Department of Aerogels and Aerogel Composites as part of the the Institute of Materials Research and to do some experiments in the laboratory on their own. After a short introduction to the material aerogel, the girls were able to prepare a hydrogel (as precursor of an aerogel) in a very simple experiment by adding diluted acetic acid to water glass solution. After that the density of resorcinol-formaldehyde aerogels was investigated in two ways which were compared to each other: mathematically (by determining volume and mass of the sample) and experimentally by using a sand pycnometer (GeoPyc, Micromeritics). Then the girls went to the chemistry laboratory, where they synthesized differentially colored alginate aerogels beads by dripping alginate solution from a burette to a CaCl2 coagulation bath. Finally they got the chance to watch the up-scaled synthesis of aerogel beads by using the Jet Cutter.