Date/Time
Date(s) - 20/06/2023
10:30 am - 11:30 am

Title: Development of Carbon Nanotubes Inks for Printed Electronics

Date: Tuesday, June 20

Time: 10:30-11:20

Room: ABB 164

Zoom: email chemgrad@mcmaster.ca for Zoom details

Host: Alex Adronov

Abstract: The mechanical, optical and electronic properties of single-walled carbon nanotubes (SWNTs) afford them a strong interest in material science. However, all current SWNT production techniques generate a heterogeneous mixture of semiconducting and metallic species and non-SWNT impurities. Therefore, their lack of purity, as well as their poor solubility in common solvents, prevent their potential applications from being realized. Different purification techniques have been developed, including the use of conjugated polymers (CPs) to selectively disperse SWNTs.¹ Different modifications on the polymer backbone and side-chains can be introduced to selectively interact with either semiconducting (sc-SWNTs) or metallic (m-SWNTs) nanotubes and produce SWNT-based inks soluble in green solvents compatible with the printing process. However, the presence of non-conductive side-chains might decrease the conductivity (?) of the resulting SWNT-based material by preventing a good contact between the nanotubes. Therefore, removing the side chains post-printing is a promising approach to lead to a higher conductivity. On the one hand, a polyfluorene backbone was functionalized with a thermally cleavable side chain containing a carbonate linker.² Upon heating at 170 °C for 17 hours, the conductivity of the cleavable sample was 20 times higher than the control sample. Dispersion in greener solvents was also investigated by functionalizing the polymer with larger cleavable polyethylene glycol (PEG) side-chains. On the other hand, a photocleavable side-chain containing an o-nitrobenzyl derivative linker has also been investigated.³ The overnight irradiation at 365 nm of the PF-oNB-SWNT complex results in the precipitation of the dispersion which indicates that the loss of side-chains eliminates the steric stabilization of the nanotubes’ dispersion. Finally, a functionalized and cleavable fluorene-based polymer copolymerized with an o-nitrobenzyl ether unit was synthesized for the release of carbon nanotubes post-dispersion.

(1) Ajayan, P. M. Nanotubes from Carbon. Chem. Rev. 1999, 99 (7), 1787–1799.

(2) Ritaine, D.; Adronov, A. Functionalization of Polyfluorene-Wrapped Carbon Nanotubes Using Thermally Cleavable Side-Chains. J. Polym. Sci. 2022, 60 (16), 1–13.

(3) Ritaine, D.; Adronov, A. Decoration of Polyfluorene-Wrapped Carbon Nanotubes with Photocleavable Side-Chains. Molecules 2023, 28, 1471.