Controlled Radical Polymerization Initiated by Solvated Electrons

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 e(sol)(-), give rise to a controlled radical polymerization (CRP) to yield polymers with predictable molecular weights and narrow molecular weight distributions (the lowest D = 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 e(sol)(-). Solvated electron (e(sol)(-)) presents distinct mechanisms in monomer initiation depending on its states. A novel controlled radical polymerization (CRP) is developed via the initiation of Na/hexamethylphosphoramide solution in states of higher molar conductivity and less paired e(sol)(-). A semi-conjugated radical carrying a negative charge is suggested to be responsible for this CRP.image