Attractive and safe chemical experiments linked to educational programmes
In the Chemistry and Light kit, you have the opportunity to combine the fluorescence module with the hydrogel module in an attractive way to prepare fluorescent hydrogels (often described as "artificial slimes", which have an impressive appearance and interesting mechanical properties.) These hydrogels are marked by their unusual behavior as non-Newtonian liquids.
During the preparation of hydrogels, the low molecular weight water-soluble polymer of polyvinyl alcohol is coordinated with boron atoms from borax. The result of this crosslinking is an abrupt increase in the molecular weight of the formed polymer and the formation of the semisolid hydrogel. In the experiment, you can dramatically demonstrate the effect of molecular weight on the properties of a polymer.
Formation of a polyvinyl alcohol-borax hydrogel is one of the most popular experiments and it also demonstrates the effect of pH on the shift of the reaction equilibrium.