Characteristics of solubilization and encapsulation of fullerene C 60 in non-ionic Triton X-100 micelles

Abstract

The solubilization and encapsulation of monomeric C 60 in Triton X-100 micelles were investigated. Characteristic hydrophobic interactions of the type π–π and CH–π between the Triton X-100 micelle and C 60 resulted in stable aqueous dispersions of C 60 in the micellar medium, as evidenced from UV–vis, fluorescence emission and micro-Raman spectroscopy. Cyclic voltammetry of C 60 encapsulated Triton X-100 in aqueous 5 mM LiClO 4 solution revealed a quasi-reversible one-electron reduction peak with E 1/2 = −0.61 V and a reversible reduction peak at E 1/2 = −1.11 V vs. Ag/AgCl reference electrode at a scan rate of 10 mV s −1, a redox behaviour drifting substantially from that of pure C 60. An onset concentration of ∼0.025 mM for C 60 aggregation in the micellar core was substantiated from the characteristic absorption spectral broadening and quenching of pyrene fluorescence. The molar solubilization capacity of C 60 in aqueous Triton X-100 micellar solution was estimated spectrophotometrically to be 0.22.