In a recent paper in Chem (Cell Press), the Sumerlin Research Group reports a new polymerization strategy that leads to the highest molecular weight polymers ever prepared by a controlled radical polymerization (CRP) method. Developments in CRP have revolutionized polymer chemistry over the last two decades, allowing access to polymers with well-defined and predictable molecular weights, narrow molecular weight distributions, block copolymers, and complex macromolecular architectures. More than 30,000 papers have been published in this area since the mid 1990?s. However, applying CRP techniques for the synthesis of high molecular weight polymers has consistently proven to be challenging.
The recent work by Nick Carmean, Troy Becker, and Michael Sims in the Sumerlin Group has shown that ultra-high molecular weight polymers can be prepared by photopolymerization of vinyl monomers in the presence of thiocarbonylthio compounds. The polymerizations occur in water, employ simple and inexpensive photoreactors, and yield well-defined homopolymers and block copolymers with ultra-high molecular weights (more than 8 million g/mol). The polymerizations can even occur via irradiation with sunlight, as demonstrated by carrying out the reactions on the roof of Sisler Hall!
For more information, see the article (http://dx.doi.org/10.1016/j.chempr.2016.12.007)
or a commentary on the work by Kamigaito and Satoh (http://www.sciencedirect.com/science/article/pii/S2451929416302753).