Fullerene containing polymers: a review on their synthesis and supramolecular behavior in solution

Due to the theoretical importance and potential applications of fullerene, numerous fullerene derivatives have been developed to enhance its solubility and processability. This article provides an overview on fullerene containing polymers, from synthesis to their physicochemical properties in solution. Due to the unique chemical structure of fullerene, different fullerene containing polymeric architecture can be synthesized through various kinds of conjugating techniques, where fullerene can be located either on the backbone or the branch chain. Recently, the successful development of azido coupling and atom transfer radical addition (ATRA) makes it possible to synthesize "controlled" and well-defined fullerene containing polymers. Experimental results indicated that fullerene containing polymers not only increase the solubility of fullerene in solution, but also retain the conjugating properties of fullerene molecules. By blocking well-defined functional polymers onto fullerene molecules, different types of stimuli-responsive amphiphilic systems can be achieved. However, the large bulk volume and high hydrophobicity of fullerene gives rise to the large aggregates with different morphologies produced in solution, which can be tuned by changing external stimuli, such as pH, temperature, salt, and co-solvents. Interestingly, fullerene containing anionic polymers could induce the formation nano-scale fractal pattern, but not fullerene containing cationic polymers, which is evident from morphological studies.