Reactive, Aqueous-Dispersible Polyfluorene-Wrapped Carbon Nanotubes Modulated with an Acidochromic Switch via Azide–Alkyne Cycloaddition

Abstract

Decorating hydrophobic carbon nanotube surfaces efficiently in aqueous solution without adversely affecting nanotube optoelectronic properties remains a challenge. In this work, we designed a water-soluble polyfluorene derivative that contains azide groups and polyethylene glycol grafts in the side chains. This polyfluorene derivative was used to coat carbon nanotube surfaces, producing a latently reactive and aqueous-dispersible polymer−nanotube complex. Reaction progress of the aqueous polymer−nanotube dispersion with various polar and nonpolar alkyne derivatives was followed using infrared spectroscopy. Decoration of the polymer−nanotube complex with various small molecules or polymers was found to modulate the surface properties of the resulting nanohybrid thin films. Additionally, we developed a vanillin-derived indolinooxazolidine switch that is functionalized with a terminal alkyne and appended it to the polymer−nanotube complex. This switch possesses two long-lived states that are interchangeable via exposure to acidic or basic conditions. We studied the fluorescence emission response of the polymer−nanotube complex using UV−vis−NIR and fluorescence spectroscopy. The acidochromic switch linked to the polymer−nanotube complex enables control over nanotube emission, while the free switch in solution does not. Photoluminescence mapping reveals a nanotube species-dependent fluorescence quenching response to charge buildup at the nanotube surface.

Synthesis of new 1,4-disubstituted 1,2,3-triazoles using the CuAAC reaction and determination of their antioxidant activities

“…Compounds 4a-e were obtained without significant differences in yield. Additionally, the structural characterisation of compounds 4a-e was consistent with reported data (Liao et al 2017, Aneja et al 2018, Teixeira et al 2018, Hussaini et al 2016, Fong et al 2019. The final step resulted in compounds 5a-e in yields ranging from 50 to 80% after chromatographic purification (Figure 3).…”

“…5, 76.6, 77.4, 109.5, 112.6, 126.2, 130.9, 149.9, 152.1, 190.8. This is in agreement with data previously reported (Fong et al 2019).…”

Light‐driven atom transfer radical polymerization on supramolecular complexes of conjugated polymers and single‐walled carbon nanotubes

“…We next prepared a polyfluorene with azide and mPEG 5000 side chains ( PF‐N 3 ‐mPEG 5000 ) and the corresponding dispersion with SWNTs, PF‐N 3 ‐mPEG 5000 ‐SWNT, following literature procedures . The polymer–SWNT dispersion process was repeated to obtain ~60 mL total of PF‐N 3 ‐mPEG 5000 ‐SWNT dispersion.…”

“…Our group has been investigating the decoration of single‐walled carbon nanotubes (SWNTs) with conjugated polymers to impart reactivity to the polymer–nanotube complex . This strategy operates by incorporating functional groups into the conjugated polymer side chains to perform chemistry on the adsorbed conjugated polymer, which avoids damage to the SWNT structure.…”

“…By incorporating azide groups into the conjugated polymer side chains, copper‐catalyzed or strain‐promoted azide–alkyne cycloaddition (CuAAC) can be used to decorate the SWNT surface. We have also incorporated aromatic iodides to enable Pd cross‐coupling to the polymer–SWNT conjugate, and have prepared water‐dispersible polymer–SWNT complexes for aqueous click functionalization . In the present work, we sought to expand this methodology by utilizing ATRP to grow polymer chains in a controlled manner from the polymer–SWNT surface.…”