Divergent Photoiniferter Polymerization-Induced Self-Assembly

Wavelength-dependent photoreactions present an opportunity to achieve chemoselectivity of functional groups that otherwise demonstrate similar reactivity under traditional thermal conditions. Relying on this concept, we demonstrate that a difunctional iniferter with two thiocarbonylthio groups can be divergently photoactivated to prepare polymeric nanoparticles via polymerization-induced self-assembly (PISA). A hydrophilic poly(oligoethylene glycol methacrylate) macroiniferter was synthesized via selective activation of one thiocarbonylthio moiety with green light. The resulting green-light-active ω-end was then further chain extended with benzyl methacrylate to obtain well-defined nanoparticles by PISA without activation of the blue-light-active α-end iniferter. The obtained nanoparticles could then be used as nanoparticle-iniferters (nanoiniferters) by chain extending from the corona with N,N-dimethylacrylamide via blue-light-mediated photoiniferter polymerization. This approach leverages the wavelength-dependent photolysis of thiocarbonylthio moieties to both synthesize and modify well-defined polymer nanoparticles.