Removable and Recyclable Conjugated Polymers for Highly Selective and High-Yield Dispersion and Release of Low-Cost Carbon Nanotubes

Abstract

High-purity semiconducting single-walled carbon nanotubes (s-SWNTs) with little contamination are desired for high-performance electronic devices. Although conjugated polymer wrapping has been demonstrated as a powerful and scalable strategy for enriching s-SWNTs, this approach suffers from significant contaminations by polymer residues and high cost of conjugated polymers. Here, we present a simple but general approach using removable and recoverable conjugated polymers for separating s-SWNTs with little polymer contamination. A conjugated polymer with imine linkages was synthesized to demonstrate this concept. Moreover, the SWNTs used are without prepurifications and very low cost. The polymer exhibits strong dispersion for large-diameter s-SWNTs with high yield (23.7%) and high selectivity (99.7%). After s-SWNT separation, the polymer can be depolymerized into monomers and be cleanly removed under mild acidic conditions, yielding polymer-free s-SWNTs. The monomers can be almost quantitatively recovered to resynthesize polymer. This approach enables isolation of "clean" s-SWNTs and, at the same time, greatly lowers costs for SWNT separation.

All‐Carbon Thin‐Film Transistors as a Step Towards Flexible and Transparent Electronics

“…[171] After separation of semiconducting CNTs, an imine-based conjugated polymer can be depolymerized into monomers and be cleanly removed under mild acidic conditions, yielding polymer-free semiconducting CNTs, as shown in Figure 5b. [172] It is desired to use a recyclable polymer to separate semiconducting CNTs, because the costs of most conjugated polymers are comparable or even higher than those of CNTs. The removable and recyclable conjugated polymers exhibit strong dispersion for large-diameter semiconducting CNTs with a yield of 23.7% and a high selectivity of 99.7%.…”

“…Although semiconductor-enriched CNT inks are commercially available, chirality-specific purification techniques such as ion-exchange chromatography [164,165] and gel chromatography [166,167] are very important to produce uniform channels. High-purity sorting of more than 99.9% semiconducting CNTs can be achieved by using charge sign reversal sorting [168] and recyclable conjugated polymer sorting [172] techniques. However, important factors including nanotube diameter and length, bundle size, morphology and the presence of a residual surfactant will considerably influence device performance, and thus require more thorough investigation.…”

Bimodal supramolecular functionalization of carbon nanotubes triggered by covalent bond formation

“…More recently, Bao and co-workers have exploited the reversibility of imine bonds for the formation and removal of a conjugated polymer that wraps around large diameter SWNTs with extreme selectivity, allowing for their facile purification. 24 …”

“…25–28 However, as illustrated by the examples described above, 22–24 the formation of oligomer-wrapped SWNTs is often advantageous.…”

Converting Waste Plastics into High Yield and Quality Carbon-Based Materials

“…[17] Particularly, in the field of synthesis, various methods have been developed for the synthesis of CNTs such as arc discharge, [18] pyrolysis, [19] laser vaporization [20] and thermal chemical vapor deposition. [21] Catalytic decomposition of hydrocarbons is a promising means to produce CNTs on a large scale.…”