Dramatic solvent effect on interaction kinetics and self-organization of phenyl-C61 butyric acid methyl ester in a triblock copolymer

The interactions of a triblock copolymer containing a PEO central and two 4VP end blocks with PCBM were studied in different solvents. The interaction is too slow to be detected in toluene, but in THF a well-defined charge transfer complex is formed, allowing the interaction kinetics to be studied. Rate constants along with other kinetic and thermodynamic parameters were determined. The 4VP units in the copolymer interact with the fullerene derivative more than two orders of magnitude faster than a small model compound. There is interplay between charge complextaion kinetics and self-assembled supramolecular micellar structures of the copolymer/PCBM system. The findings should provide useful insight in design and formation of nanoscale domains of fullerene and derivatives in polymer blend systems. The interaction kinetics of complexation, in solution, of PCBM and 4-vinyl pyridine moieties (4VP) is studied, where the components are either used as end blocks of a triblock copolymer or as small molecular model compounds. The results may help to understand and control the self-assembly of electrically active fullerenes, which can be of considerable interest for optoelectronic device applications.