Fig. 5
From: Destabilization of Surfactant-Dispersed Carbon Nanotubes by Anions
Schematic diagrams of the free energy of the surfactant-dispersed SWCNTs for the SWCNT association-governed system (system 1) and the SWCNT migration-governed system (system 2). The free energy difference (ΔΔG) is calculated by subtracting the stability of SWCNTs in the no additive solution (ΔG w) from that in the salt solution (ΔG s), i.e., ΔΔG = ΔG s − ΔG w. a System 1: The associated SWCNTs are relatively stabilized in the presence of salts, i.e., ΔΔG < 0, because the chemical potential of the individually dissociated SWCNTs (μ d) is more significantly increased by the addition of salts than that of the associated SWCNTs (μ a) owing to the difference in surface area. b System 2: SWCNTs in phase-h, i.e., the ATP top phase or the column gel phase, are relatively destabilized in the presence of salts, i.e., ΔΔG > 0, because the chemical potential of the SWCNTs in phase-h, depicted by μ h, is more significantly increased by the addition of salts than that of the SWCNTs in phase-l, i.e., the ATP bottom phase or the column mobile phase, depicted by μ l. The transfer free energy (ΔG tr) is calculated by subtracting the chemical potential of SWCNTs in the no additive solution from that in the salt solution (Eq. 2) [56].