Facile access to coil-rod-coil-type block copolymers by CuAAC-based macromolecular clicking

Defect-free and perfectly linear polyarylenebutadiynylenes can be readily synthesized through acetylenic oxidative polymerizations of diethynyl arene monomers. Although these polymers are ideal semiconducting polymers with a rigid main chain backbone, they often have solubility issues even with the introduction of alkyl side chain groups. We recently reported the synthesis of a poly(thieno[3,2-b]thiophen-2,5-diylbutadiynylene) derivative and its semicrystalline feature due to the limited solubility of this compound. To increase the processability of this polymer in solution, we utilized a Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) click postfunctionalization to introduce polystyrenes into the polymer terminals. The molecular weights estimated from gel permeation chromatography (GPC) were reasonably increased, and the temperature-dependent absorption spectra suggested that the CuAAC-based functionalization was successful and furnished a coil-rod-coil type triblock copolymer. The resulting block copolymer exhibited higher solubilities in common organic solvents, but the electronic properties of the poly(thieno[3,2-b]thiophen-2,5-diylbutadiynelene) unit were retained in the solid thin film state.

Automated summary

Defect-free and linear polyarylenebutadiynylenes with improved solubility were synthesized through postfunctionalization using a Cu(I)-catalyzed click reaction. The resulting triblock copolymer exhibited higher solubilities in organic solvents while retaining the electronic properties of the original polymer unit.