In-depth study into the interaction of single walled carbon nanotubes with anthracene and p-terphenyl

Solubilization of single walled carbon nanotubes (SWNT) in the presence of polycyclic aromatic hydrocarbons (PAHs) such as p-terphenyl and anthracene has been shown. The suspensions formed are stable for periods greater than 48 months but to date experimental research is scarce regarding the interactions that are taking place. Spectroscopic analysis such as Raman and fluorescence are used to probe the interactions occurring between the PAHs and the SWNT over a wide concentration range. Previous studies show the fluorescence of the PAHs is quenched on interaction with SWNT and in the case of p-terphenyl, the spectrum is red shifted. This result prompted a study of a large range of concentrations to quantify the degree of interaction between the SWNT and PAHs. It was found at high concentrations that both the PAHs and SWNT formed aggregates and at lower concentrations it was found that free PAHs and isolated SWNT were interacting. The radial breathing modes (RBMs) in Raman spectroscopy gave detail as to how diameter selective the PAH samples are when compared to the pristine SWNT modes. An increase in the wavenumber of the RBMs for both composite spectra was observed and it is believed that such a result is due to the debundling of the SWNT on interaction with the PAHs. It was also found that anthracene and p-terphenyl selectively interact with SWNT and the selected SWNT were found to be within a distinct diameter range and possessed unique physical properties.