The Effect of Electrochemical Treatment on the Structure of Single-Walled Carbon Nanotubes: Towards Better Filling Efficiency

Filled single-walled carbon nanotubes (f-SWCNT) are regarded as prospective materials with diverse applications, owing to the superior combination of their intrinsic properties with those of the filler material. The variety of the potential filler materials makes solution filling through open SWCNT channels under capillary forces the most flexible method for f-SWCNT production. However, the technique requires the additional step of SWCNT cap removal, and remains poorly efficient. Here, we evaluated how the structure of the SWCNTs impacts the filling efficiency depending on the conditions of electrochemical opening treatment under cyclic voltammetry protocols. We revealed the optimal upper vertex potential to be 1.1 V vs. RHE, corresponding to the trade-off between end-cap removal efficiency and yield of wall defect formation. It allowed us to achieve a filling efficiency of ∼1680 m cm−2 of gold nanowires length per unit SWCNT film area, which is ∼10 times greater than the filling efficiency of the untreated material.