Visible Light Induced RAFT Polymerization of 2-Vinylpyridine without Exogenous Initiators or Photocatalysts

The controlled radical polymerization of 2-vinylpyridine is reported using commercial blue light-emitting diodes as visible light source in the presence of S-1-dodecyl-S-(,-dimethyl--aceticacid) trithiocarbonate without exogenous initiators or photocatalysts. With this system, poly(2-vinylpyridine) with well-regulated molecular weight and narrow dispersity (D) (D = 1.13) and a conversion efficiency of 84.9% is obtained after 9 h irradiation. The polymerization can be instantly switch on or off in response to visible light while maintaining a linear increase in molecular weight with conversion and first order kinetics. These results demonstrate the simplicity and efficiency of the photocatalysts-free, visible light mediated reversible addition fragmentation chain transfer polymerization as a platform to achieve well-defined poly(2-vinylpyridine) under mild conditions.