Controlled Synthesis of Ultralow-Defect Poly(vinylidene fluoride) via Organocatalyzed Low-Temperature Polymerization

Polyvinylidene fluoride (PVDF), distinguished for its exceptional electroactivity, holds considerable promise for applications in flexible and wearable electronics. However, its performance is limited by intrinsic chain defects during radical addition. We demonstrate that temperature critically governs defect formation and exploit this insight to develop a wide-temperature-range (-40 to 50 °C), organocatalyzed photoredox polymerization to enable controlled PVDF synthesis. The synergy of low-temperature propagation and reductive initiation not only suppressed chain defects to 1.8% by enforcing regioselective head-to-tail addition but also shifted chain-end connections from the VDF tail (CH₂) to the more active head (CF₂). The defect control promoted the formation of the β-phase, achieving a dielectric constant 40% higher than conventional PVDFs (12.7 vs 9). Moreover, this method unlocks PVDF's potential as a modular building block, enabling on-demand access toward previously unattainable structural diversity. This work overcomes a long-standing bottleneck in electroactive polymer design, opening avenues to tailor primary structures for advanced flexible electronics.