Dispersion and Exfoliation of Nanotubes with Synthetic Oligonucleotides: Variation of Dispersion Efficiency and Oligo-Nanotube Interaction with Base Type J. Marguerite Hughes Helen Cathcart Jonathan N. Coleman 10.1021/jp101834t.s001 https://acs.figshare.com/articles/journal_contribution/Dispersion_and_Exfoliation_of_Nanotubes_with_Synthetic_Oligonucleotides_Variation_of_Dispersion_Efficiency_and_Oligo_Nanotube_Interaction_with_Base_Type/2752663 Single walled carbon nanotubes (SWNTs) were dispersed and exfoliated in four different homopolymer oligonucleotides (dA<sub>15</sub>, dG<sub>15</sub>, dC<sub>15</sub>, and dT<sub>15</sub>). The dispersed nanotube concentration and degree of exfoliation were measured for each nucleobase. The nanotubes were more highly exfoliated and more temporally stable in dC<sub>15</sub> and dT<sub>15</sub>. While the degree of exfoliation was relatively time independent, absorption and photoluminescence spectra showed definite changes over time after the initial sample preparation. In particular, photoluminescence signals appeared at well-defined times, consistent with previous evidence of time-dependent DNA wrapping followed by oxide removal. Analysis of the nanotubes’ optical properties, including circular dichroism, suggests that all bases except adenine stack onto the nanotube surface. In contrast, dA<sub>15</sub> is unstable on the nanotube surface and eventually returns to a self-stacked arrangement. The order of the dispersion efficiencies was found to be T > C > G ≫ A, where thymine produced the most intense NT optical signals and cytosine was seen to wrap SWNTs the fastest. 2010-07-15 00:00:00 nanotube surface NT DNA SWNT