Acid-Mediated Autocatalysis in Vinylogous Urethane Vitrimers.

Vitrimers are a class of polymeric materials with outstanding properties. Intramolecular substitution reactions lead to a dynamic exchange within the polymer network which enables thermoreversible stress relaxation in yet permanently crosslinked materials. In this paper, the acid-mediated autocatalysis is explored as a rearrangement pathway for vinylogous urethane vitrimers.

Novel and easy access to highly luminescent Eu and Tb doped ultra-small CaF, SrF and BaF nanoparticles - structure and luminescence.

A universal fast and easy access at room temperature to transparent sols of nanoscopic Eu and Tb doped CaF, SrF and BaF particles via the fluorolytic sol-gel synthesis route is presented. Monodisperse quasi-spherical nanoparticles with sizes of 3-20 nm are obtained with up to 40% rare earth doping showing red or green luminescence. In the beginning luminescence quenching effects are only observed for the highest content, which demonstrates the unique and outstanding properties of these materials.