Dispersed multi-walled carbon nanotubes in polyvinyl butyral matrix for transparent ionic conductive films

Abstract

In this work, we develop methods for increasing the dispersion degree of agglomerated multiwalled carbon nanotubes with subsequent introduction of them into polyvinyl butyral to create transparent conductive films. The influence of proton and a-proton solvents in combination with potassium triiodide (KI3) as a redox component for oxidation of the multiwalled carbon nanotubes surface, which reduces agglomeration due to electrostatic repulsion, is investigated. It is demonstrated that a-proton solvent cyclohexanone ensures a smaller size of the agglomerates (30-300 nm, with a maximum of ~145 nm) compared to proton solvent propyl alcohol (100-3000 nm, with a maximum of ~920 nm). The reduced aggregation is associated with the formation of oxygen-containing functional groups (C=O, C-O, C-O-C, and COO), which increase electrostatic stabilization. The impedance analysis showed that the constant component of the conductivity in the samples with multiwalled carbon nanotubes and a-proton solvent shifts to frequencies of ~104 rad/s after the addition of the redox component, which indicates the formation of ion-conducting channels and stabilization of the jump charge transfer.