Aqueous dispersions of C60 fullerene by use of amphiphilic block copolymers:: Preparation and nonlinear optical properties

The dispersion of the otherwise insoluble C-60 fullerene in water is discussed. Amphiphilic block copolymers, namely, polystyrene-b-polyethylene oxide (PS-PEO), were found to be able to disperse C-60 in aqueous solutions, where the polymer forms micelles with a hydrophobic PS core. The preparation protocol of the final solutions was found to play a crucial role in the ability of the block copolymer to disperse the C-60 molecules. The C-60 containing aggregates were studied using optical spectroscopy, light scattering, and scanning electron microscopy. In addition, their optical limiting action and nonlinear optical properties under visible nanosecond laser excitation were studied and compared with that of C-60-toluene solutions.