Relationship Between Primary Structure and Hansen Solubility Parameter of Carbon Nanotubes

We develop a new method to experimentally evaluate solubility parameter which is a dominant parameter for mixing Gibb's energy Delta G(mix). We estimate solubility parameter of several CNTs from solubility of CNT for organic solvents. Furthermore, we decompose solubility parameter of CNTs into Hansen solubility parameters using the Hansen sphere method. Hanse solubility parameters are consist of dipolar intermolecular force between molecules delta P, dispersion forces between molecules delta(D), and hydrogen bonds between molecules delta(H). Finally, we propose that the each Hanse solubility parameters (delta(P), delta(D), and delta(H)) are closely related with primary structure of CNTs, such as G/D ratio, diameter and functional group of CNTs. This finding may be useful for controlling solubility parameter of CNT for decreasing Delta G(mix) of CNT solution and composites.