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 pi-pi and CH-pi 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 voltarnmetry of C-60 encapsulated Triton X-100 in aqueous 5 mM LiClO4 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 similar to 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. (C) 2008 Elsevier Ltd. All rights reserved.