A signature of photo-mediated controlled polymerizations is the ability to modulate polymerization by turning the light source ‘on’ and ‘off’, typically referred to as temporal control. However, in many reported systems, growth can be reproducibly observed during dark periods. In this contribution, widely used photo-mediated controlled radical polymerizations (Cu ATRP, metal-free ATRP, PET-RAFT) are evaluated with a high degree of precision to assess their behavior in the dark. Detailed polymerization kinetics, collected using in situ NMR spectroscopy, distinguish photo-mediated controlled radical systems with ideal and non-ideal temporal control. Of particular note is the observation that Cu ATRP systems undergo long-lived, linear growth during dark periods in organic media. Importantly, huge differences between organic media and eco-friendly solvents like water are also observed and will be discussed.

What happens in the dark in organic and aqueous media? Assessing the temporal control of photo-mediated radical polymerizations

2019 Fall National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.