posted on 2023-12-15, 20:38authored bySantosh Adhikari, Ivana Matanovic, Daniel Leonard, Jeffrey M. Klein, Tanya Agarwal, Yu Seung Kim
We report a rapid postgrafting reaction
to prepare alkyl ammonium
functionalized polycarbazoles from a commercially available monomer.
This novel synthetic approach provides benefit to preparing the high
molecular weight quaternized polycarbazoles within 1 h of Friedel–Crafts
polycondensation, avoiding the synthesis and purification step to
prepare a functionalized monomer. The postgrafting reaction produces
hexyl alkyl ammonium functionalized polycarbazole with 100% grafting
degree. However, the postgrafting reaction produced only 60% grafting
with propyl alkyl ammonium due to the competitive elimination reaction
because of the higher acidity of β-hydrogen in the propyl alkyl
group resulting from the proximity of the bromide and ammonium groups.
The hexyl alkyl ammonium functionalized polycarbazole has a high hydroxide
conductivity of 103 mS cm–1 at 80 °C and showed
excellent alkaline stability with less than 3% loss of ion group after
1 M NaOH treatment at 80 °C for 500 h. This study highlights
that the postgrafting reaction provides a pathway for the scale-up
synthesis of quaternized aryl ether-free polyaromatics.