Post‑Functionalization Engineering of Semiconducting Polymers Bearing Multiple Hydrogen‑Bonding Motifs for Robust Stretchable Transistors

Stretchable polymer semiconductors are key enablers for next‑generation wearable electronics but remain constrained by a fundamental stretchability–mobility trade‑off. Established molecular design strategies include incorporating long, flexible alkyl side chains or, more effectively, introducing hydrogen‑bonding motifs that function as dynamic cross‑links capable of dissipating mechanical energy and enabling network reorganization under strain while preserving charge transport. Attaching quadruple hydrogen‑bonding units into conjugated polymer side chains or backbones can generate supramolecular networks with enhanced mechanical robustness, yet this often demands careful structural engineering to avoid perturbing π‑conjugation and charge‑carrier pathways. In this work, we employ a post‑functionalization strategy to graft ureido‑pyrimidinone (UPy) units onto diketopyrrolopyrrole‑based polymers (PDPP2T) containing (6‑bromohexyl)oxy(tert‑butyldimethylsilane) (OTBS) linkers, yielding a PDPP2T‑UPy‑x series with 0, 2, and 5 mol% UPy (D0, D2, and D5). This architecture installs two hierarchically organized hydrogen‑bonding motifs along extended alkyl side chains, namely weaker mid‑chain urethane linkages and strong terminal quadruple UPy units. As a consequence, D5‑based transistors retain mobilities within the same order of magnitude as the pristine devices (3.02–1.12 × 10⁻¹ cm² V⁻¹ s⁻¹) after 500 stretching cycles at 100% strain. This level of mobility retention surpasses typical intrinsically stretchable semiconducting polymers, demonstrating that post‑synthetic control over hierarchical hydrogen‑bond density can reconcile mechanical compliance with efficient charge transport without direct modification of the conjugated backbone, and offers a generally applicable platform for other conjugated polymer systems.