POSS core molecules have a considerable amount of free volume around the core. Photochromic switching can benefit from access to such free volume. The integration of such functionalized POSS nanoparticles into polymer coating and resins then provides useful photochromic materials that can not only toughen the product but also are able to switch rapidly between the two photochrmic light/dark states. The design, synthesis, characterization and thermal analysis of novel Octa-Azobenzene POSS photochromic “Supermolecules” (see figure below) will be presented. These supermolecules needed to be synthesized via a divergent route, using hydrosilylation to generate high yielding diazonium salt chemistry, that was then used to produce a variety of azobenzene “arms” with different peripheral functional groups. An aliphatic spacer component was introduced into the organic arms extending from the POSS core molecule, resulting in some liquid crystalline properties. With nitro groups on the periphery, the azobenzene groups are electron donor/acceptors and therefore suitable for use in electro-optic materials. In addition, the terminal carboxylic acid functionality offers access to star-like crosslinking materials as well as thermoset nanocomposite materials.

Way to faster switching in photochromics using polyoligohedralsilsesquioxane nanoparticles

2019 Spring National Meeting

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