Design, Synthesis, and Characterization of Semiconducting Polymers Incorporating a Ring-like Ureidopyrimidinone (UPy) Quadruple Hydrogen Bonding Structure

Introducing hydrogen bonding structures into semiconducting polymers is an effective method to enhance the intra/interchain interactions and improve the overall performance of the polymer. In this study, diketopyrrolopyrrole (DPP)-based random copolymers with quadruple hydrogen bonding in the backbone are constructed by the copolymerization of a rationally designed ring-like tetrahydrogen-bonded ureidopyrimidinone (UPy) with alkyl chain-substituted DPP using a new design strategy via intramolecular hydrogen bonding. Specifically, ring-like UPy structures with different ratios were introduced into DPP-based conjugated polymers by the Stille coupling. The electrical and mechanical properties of the resulting series polymers were characterized before and after stretching. The copolymer’s tensile properties were improved owing to the introduction of the ring-like UPy unit, with 27.9% mobility retention under 100% stretching. More importantly, intramolecular quadruple hydrogen bonding was unprecedentedly introduced into the backbone of conjugated polymers, developing a new strategy for the introduction of multiple intramolecular hydrogen bonds into conjugated polymers conveniently and, more promisingly, enriching structural types of stretchable semiconductor polymers.