Controlled Radical Polymerization Initiated by Solvated Electrons

Abstract

Solvated electron (esol−) is highly reducing species and apt to initiate monomers via one-electron transfer reaction. Herein, utilizing the esol− solution of Na/hexamethylphosphoramide, radical and anionic initiations are observed respectively, which heavily depend on Na concentrations. Interestingly, this initiation system, in states of lower Na concentrations, higher molar conductivities and less paired esol−, give rise to a controlled radical polymerization (CRP) to yield polymers with predictable molecular weights and narrow molecular weight distributions (the lowest Ð = 1.25). This CRP presents unique behaviors, like solvent effect, electric field effect, and unusual copolymerization phenomenon. A semi-conjugated radical carrying a negative charge is proposed to be responsible for the CRP. This system gives a distinct way to regulate CRP from current CRPs, and offers new insights into the monomer initiation by esol−.