Synthesis of Buckminsterfullerene C60 functionalised core cross-linked star polymers

Buckminsterfullerene C60 core functionalised core cross-linked star (CCS) polymers have been prepared for the first time, using atom transfer radical polymerisation and the arms-first approach. A simple and efficient method is presented which allows the construction of star polymers consisting of a large number of arms and multiple units of C60 per core, far in excess of that obtained previously. The C60 CCS polymers were characterised by gel permeation chromatography (GPC), UV-vis spectroscopy and cyclic voltammetry (CV). GPC revealed that the C60 CCS polymers possess weight average molecular weights (Mw) ranging from 172-411 kDa and up to 30 arms per macromolecule. The average number of molecules of C60 per CCS polymer core was found to be dependent on the C60/PMMA ratio employed and was determined by UV-vis spectroscopy to range up to 6.2. CV revealed that, like pristine C60, the C60 CCS polymers possessed three reversible one electron reductions. However, the reduction potentials were positively shifted, implying that the electron affinity of these macromolecules is higher than pristine C60.