Polyelectrolyte-Containing Fullerene I: Synthesis and Characterization of the Copolymers of 4-Vinylbenzoic Acid with C60

Polymerization of 4-vinylbenzoic acid in the presence of C 60 using free radical initiator resulted in covalent incorporation of C 60 in the polymer structure. Incorporation of the C 60 moieties in the polymer was established by IR, NMR, and UV−vis spectroscopy. The solution UV−vis spectra of these C 60 -containing copolymers appear to be dominated by scattering, obscuring specific electronic excitation features associated with the fullerene. UV−vis spectral analysis of filtrate fractions collected using filters of varying pore sizes indicates that polymers form microgels with polydisperse particle sizes (micron to submicron dimensions) in solution that extensively scatter at shorter wavelengths. Differences in the fluorescence properties of the filtered fractions and unfiltered samples were observed. Furthermore, fluorescence emission spectra of a copolymer showed wavelength-dependent behavior. Polyelectrolyte behavior of these copolymers was studied by concentration dependent viscosity changes of the polymers in aqueous NaOH solutions of varying ionic strength. These copolymer microgels formed stable monolayers at the air−water interface of a Langmuir−Blodgett film balance. Solubilization of these polymers in dilute alkali solution offers a novel route to prepare fullerene-containing polyelectrolytes.