Precise Synthesis of Ultra‐High‐Molecular‐Weight Fluoropolymers Enabled by Chain‐Transfer‐Agent Differentiation under Visible‐Light Irradiation

Ultra‐high‐molecular‐weight (UHMW) polymers display outstanding properties and hold potential for wide applications. However, their precise synthesis remains challenging. Herein, we developed a novel reversible‐deactivation radical polymerization based on the strong and selective fluorine–fluorine interaction, allowing chain‐transfer agents to spontaneously differentiate into two groups that take charge of the chain growth and reversible deactivation of the growing chains, respectively. This method enables dramatically improved livingness of propagation, providing UHMW polymers with a surprisingly narrow molecular weight distribution (Đ≈1.1) from a variety of fluorinated (meth)acrylates and acrylamide at quantitative conversions under visible‐light irradiation. In situ chain‐end extensions from UHMW polymers facilitated the synthesis of well‐defined block copolymers, revealing the excellent chain‐end fidelity achieved by this method. Fluorpolymere werden lebendig: Eine photovermittelte radikalische Polymerisation mit reversibler Deaktivierung wurde auf der Grundlage eines neuartigen CTA‐Differenzierungsmechanismus (CTA: chain transfer agent) entwickelt. Die Methode ernöglicht die präzise Herstellung von Fluorpolymeren mit ultrahohen Molekulargewichten, engen Molekulargewichtsverteilungen und ausgezeichneter Kettenendentreue.