“Click” generation of a conjugated polymer library for SWNT dispersion

Abstract

Noncovalent functionalization of single‐walled carbon nanotubes (SWNTs) with conjugated polymers enhances SWNT processability and allows for selective dispersion of various SWNT species. Selective dispersions can be obtained by tuning the nature of the polymer, which can involve using various polymer backbones or side‐chains. However, a clear understanding of selectivity determinants is elusive, as the degree of polymerization (DP) has a large effect on SWNT selectivity. Additionally, preparing libraries of conjugated polymers with varying functionality while keeping DP consistent is difficult. Here, we report the utilization of a strained cyclooctyne‐containing conjugated polymer that serves as a versatile scaffold, enabling systematic preparation of a small library of conjugated polymers with different side‐chain functionality, while maintaining a consistent DP. The resulting polymers were used as dispersants for SWNTs, forming supramolecular polymer‐SWNT complexes that were characterized by UV‐Vis‐NIR absorption and Raman spectroscopy. In the series of polymers, we were able to probe the effect of small changes within the side chains, such as the incorporation of a carbonyl group or an aromatic unit, on the quality of the polymer‐SWNT dispersion. The results of these studies provide new insight into the factors that dictate the ability of a polymer to form strong interactions with SWNTs. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 2053–2058

Separation of Semiconducting Carbon Nanotubes Using Conjugated Polymer Wrapping

“…Polymer side chains play an important role in adjusting the solubility of the polymer and altering its interaction with the SWNTs as well as with the solvent [ 82 ]. The side chain effects on sorting have been studied in many polymer systems ( Figure 7 ) [ 65 , 88 , 89 , 90 , 91 ].…”

“…Polymer side chains play an important role in adjusting the solubility of the polymer and altering its interaction with the SWNTs as well as with the solvent [82]. The side chain effects on sorting have been studied in many polymer systems (Figure 7) [65,[88][89][90][91]. Bao et al studied the sorting properties of rr-P3ATs (P7-P10) (P26), and they found that, by increasing the side chain length, the sorting yield of s-SWNTs would increase [65,66].…”

A Survey of Strain‐Promoted Azide–Alkyne Cycloaddition in Polymer Chemistry

“…The main advantage of a reactive polymer backbone is the ability to tune the side chain of a polymer toward a specific application, while maintaining the polymer backbone and degree of polymerization (DP). Specifically, using this system we probed the effect of polymer side‐chain structure on SWNT dispersion quality [89] . To confidently ascertain structure–activity relationships, it was critical to maintain constant DP within the polymer library, as previous studies have shown that polymer length significantly impacts the resulting polymer–SWNT dispersion [90] .…”

“…Specifically,u sing this system we probed the effect of polymer side-chain structure on SWNT dispersion quality. [89] To confidentlya scertain structure-activity relationships, it was criticalt om aintain constantD Pw ithin the polymer library,a sp revious studies have shown that polymer length significantly impacts the resultingp olymer-SWNT dispersion. [90] We found that the introductiono fa na-arylketone moiety significantly improved the polymer's ability to disperse SWNTsr elative to the aryl ring alone.…”

Click‐Functionalization of a Poly(Tetrazine‐co‐Fluorene)‐Conjugated Polymer with a Series of trans‐Cyclooctene Derivatives

“…[23] In previous work, we have shown that post-polymerization functionalization of ad ibenzocyclooctyne (DIBO)containing conjugated polymer is possible via strain-promoted alkyne-azide cycloaddition (SPAAC). [24][25][26] Not only is SPAACf unctionalization rapid (2 nd order rate constant of 0.031 M À1 s À1 ), but the reaction was shown to be efficient enough to quantitatively functionalize the polymer backbone with 24 kDa polystyrene azide,resulting in agraft copolymer having an umber average molecular weight (M n )e xceeding 800 kDa. [24] Though av ersatile polymer,t he DIBO-containing polyimine is plagued with poor hydrolytic stability, [27] and the multi-step synthesis to the monomer is prohibitive to its applications (six steps;o verall yield of 7%).…”