Tailor‐Made Poly(vinylamine) via Purple LED‐Activated RAFT Polymerization of N‐vinylformamide

Photo‐iniferter reversible addition‐fragmentation chain transfer (PI‐RAFT) polymerization of N‐vinylformamide (NVF) is demonstrated by using purple light. PNVFs with predetermined molar masses and narrow molar mass distributions are obtained. High RAFT chain‐end fidelity is confirmed by matrix‐assisted laser desorption ionization time‐of‐flight (MALDI‐TOF) and electrospray‐ionization time‐of‐flight mass spectrometry (ESI‐TOF‐MS), and chain extension experiment. To demonstrate the potential of this approach, an original poly(N‐vinylpyrrolidone)‐b‐poly(N‐vinylformamide) (PVP‐b‐PNVF) diblock copolymer is synthesized and characterized by aqueous size‐exclusion chromatography (SEC), asymmetric flow field‐flow fractionation (A4F), and 1H diffusion‐ordered spectroscopy nuclear magnetic resonance (1H DOSY NMR). Finally, selective hydrolysis of PNVF block to corresponding pH‐responsive poly(N‐vinylpyrrolidone)‐b‐poly(N‐vinylformamide) (PVP‐b‐PVAm) is performed. Photo‐iniferter reversible addition‐fragmentation chain transfer (PI‐RAFT) of N‐vinylformamide (NVF) is demonstrated by using purple LED light. Excellent control over molar masses is achieved, with low dispersities. An original poly(N‐vinylpyrrolidone)‐b‐poly(N‐vinylformamide) (PVP‐b‐PNVF) diblock copolymer is synthesized and characterized by aqueous size‐exclusion chromatography (SEC), asymmetric flow field‐flow fractionation (A4F), and 1H diffusion‐ordered spectroscopy nuclear magnetic resonance (1H DOSY NMR). Selective hydrolysis of PNVF block gives access to the corresponding pH‐responsive poly(N‐vinylpyrrolidone)‐b‐poly(N‐vinylformamide) (PVP‐b‐PVAm).