Molecular simulation on solubilization of fullerene C ₆₀ by C ₁₂ E ₆ nonionic surfactants

Coarse grained simulations were adopted to describe the encapsulation and dispersion of fullerene C 60 by hexaoxyethylene dodecyl ether (C 12E 6) surfactants. The self-organised structures of C 12E 6 molecules in water were captured and the characteristics of micelles composed of different number of C 12E 6 molecules were analysed. We found that C 60 molecules alone or in clusters can spontaneously translate into the hydrophobic core of micelles. One monomeric C 60 can explore the hydrocarbon-chain region of the micelles with different sizes, and two different preferential locations of C 60 are observed. The small C 60 clusters can disaggregate after entering the micelle. Larger C 60 clusters can penetrate into the micelle as solid-like nanoparticles, although they are partially disaggregated. When investigating the self-assembly of C 12E 6 surfactants and C 60 molecules, we found that it is very difficult to disperse C 60 in the micelle monomolecularly. At high molar ratio of C 12E 6/C 60, colloidal nanoC 60 aggregates form with C 12E 6 surfactants adsorbed on the surface. Our simulations provide an explanation for the different observations in fullerene solubilization in micellar solutions and give a guideline for further solubilization of pristine fullerene or small hydrophobic molecules with surfacant micelles, which is helpful for the design of new micelle-based delivery vehicles.