Effect of Polymer Molecular Weight and Solution Parameters on Selective Dispersion of Single-Walled Carbon Nanotubes

Abstract

The selective dispersion of single-walled carbon nanotube species (n,m) with conjugated polymers such as poly(9,9-dioctylfluorene) (PFO) and poly(9,9-dioctylfluorene-co-benzothiadiazole) (F8BT) in organic solvents depends not only on the type of solvent but also on the molecular weight of the polymer. We find an increasing amount of nanotubes and altered selectivities for dispersions with higher molecular weight polymers. Including the effects of different aromatic solvents, we propose that solution viscosity is one of the factors influencing the apparent selectivity by changing the reaggregation rate of the single-walled carbon nanotubes (SWNT). The type of solvent, polymer molecular weight, concentration, and viscosity should thus be taken into account when screening for new polymers for selective SWNT dispersion.

Photoinduced p‐ to n‐type Switching in Thermoelectric Polymer‐Carbon Nanotube Composites

“…[ 33 ] The efficiency and selectivity to particular CNT chiralities depends on a variety of factors, such as the type of polymer (determining the specifi c π-π interactions), the molecular weight of the polymer, and the length and type of side chains. [34][35][36][37] Here, we set out to investigate if n-type organic composites could be obtained by mixing a p-type conjugated polymer with nitrogen doped n-type CNTs. We chose poly(3-hexylthiophene) (P3HT) since it can show ambipolar transport [ 38 ] and can wrap around CNTs.…”

Nanoscale Charge Percolation Analysis in Polymer‐Sorted (7,5) Single‐Walled Carbon Nanotube Networks

“…Although the exact selection mechanism is still debated, the number and type of side-chains, the molecular weight of the dispersing polymer, the concentration as well as the viscosity of the solvent seem all to affect the polymers selectivity toward semiconducting SWNTs. [33] Figure 1 shows the absorption spectrum of the polymer-sorted (7,5) SWNTs dispersion in chlorobenzene. The chemical structure of the PFO is shown in the inset.…”

Semiconducting single-walled carbon nanotubes sorting with a removable solubilizer based on dynamic supramolecular coordination chemistry

“…In order to preserve the intrinsic SWNT properties, the latter method has an advantage over the former one. Recently, various methods for the separation of sem-and met-SWNTs including wrapping by SWNT solubilizers, such as DNAs 20,21 and p-conjugated or non-conjugated copolymers 11,[22][23][24] , density gradient ultracentrifugation 25,26 and gel chromatography techniques 12,14,[27][28][29][30][31][32][33][34][35][36][37][38][39] , have been reported. However, the reported techniques are rather complex and the efficiency is not very high.…”

“…Moreover, we revealed that the PFO copolymers with a bulky optically active moiety could separate the right-and left-handed sem-SWNTs 35 . However, there are several serious problems when using PFOs; that is, difficulty in the removal of the wrapped PFOs from the SWNT/PFO composites 36,37 as well as their low extraction efficiency from the as-produced SWNTs 30,31 .…”