Selective interaction between nanotubes and perylene-based surfactant

We recently reported a significant deviation in the photoluminescence intensities of HiPco nanotubes solubilized with a perylene-based surfactant, C16, compared to bile salt surfactants. For C16, the photoluminescence emission of chiralities (9,5), (10,3), and (11,1) is enhanced by up to 430%. Resonant Raman spectroscopy is less sensitive to bundling state and also yields disparate chirality intensity ratios: The (11,0) zigzag tube signal increases by 100% compared to (8,6), (9,4), and (10,2) after suspension with C16. We also report the change in photoluminescence intensity distribution after the swelling of bile salt suspended nanotubes with a series of small organic chromophores in DCM. These changes are attributed to chromophore-induced surfactant reorganization, resulting in better nanotube individualization. The chirality for which the PL intensity is most enhanced is (11,1) for all chromophores, a chirality also increased by 300% in the C16-solubilized sample. Conjointly, these measurements indicate that both preferential solubilization and enhanced debundling contribute to the PL intensity distribution in the C16-solubilized nanotube sample. This has wide ranging implications for the design of chirally selective surfactants and the demonstration of their selectivity, which is typically only shown through luminescence measurements.