Solubilization of single-wall carbon nanotubes in Organic solvents without sidewall functionalization
Robin E Anderson1, Andrew R Barron
1Richard E. Smalley Institute for Nanoscale Science and Technology, Rice University, Houston, Texas 77005, USA.
Abstract:
Single walled carbon nanotubes (SWNTs) may be made soluble in a range of organic solvents without sidewall functionalization via their reduction by Na/Hg amalgam in the presence of dibenzo-18-crown-6. The [Na(dibenzo-18-crown-6)]n[SWNT] complex has been characterized by UV-Visible, Raman, and AFM and is consistent with no additional sidewall functionalization as compared with raw SWNTs, while MALDI-MS shows the presence of the [Na(dibenzo-18-crown-6)]+ ion. Solubility is greatest in CH2Cl2 and DMF being comparable to surfactant dispersed SWNTs, however, measurable solubilities are also observed in hexane, toluene, and alcohols. Reaction with alkyl halides (bromohexane, 1-iodododecane) yields alkyl functionalized SWNTs (i.e., C6H11-SWNTs and C12H25-SWNTs) with an C(SWNT):alkyl ratio (ca. 40:1) significantly lower than that observed by the analogous reaction of alkyl halides with reduced SWNTs formed by the Billups method in liquid ammonia.
