(Co-)solvent selection for single-wall carbon nanotubes: bestsolvents, acids, superacids and guest–host inclusion complexes

Abstract

Analysis of 1-octanol–water, cyclohexane–water and chloroform (CHCl₃)–water partition coefficients P_o–ch–cf allows calculation of molecular lipophilicity patterns, which show that for a given atom log P_o–ch–cf is sensitive to the presence of functional groups. Program CDHI does not properly differentiate between non-equivalent atoms. The most abundant single-wall carbon nanotube (SWNT), (10,10), presents a relatively small aqueous solubility and large elementary polarizability, P_o–ch–cf and kinetic stability. The SWNT solubility is studied in various solvents, finding a class of non-hydrogen-bonding Lewis bases with good solubility. Solvents group into three classes. The SWNTs in some organic solvents are cationic while in water/Triton X mixture are anionic. Categorized solubility is semiquantitatively correlated with solvent parameters. The coefficient of term β is positive while the ones of ε and V negative. The electron affinity of D-glucopyranoses (D-Glcp_n) suggests the formation of colloids of anionic SWNTs in water. Dipole moment for D-Glcp_n-linear increases with n until four in agreement with 18-fold helix. The I_n^z− and SWNT⁻ are proposed to form inclusion complexes with cyclodextrin (CD) and amylose (Amy). Starch, D-Glcp, CD and Amy are proposed as SWNT co-solvents. Guests–hosts are unperturbed. A central channel expansion is suggested.