Novel tetraphenylethylene (TPE)-functionalized nitroxide/alkoxyamine for nitroxide-mediated homogeneous and heterogeneous polymerizations

Tetraphenylethylene (TPE)-containing 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl (NH₂-TEMPO) and 3-(((2-cyanopropan-2-yl)oxy)(cyclohexyl)amino)-2,2-dimethyl-3-phenylpropanenitrile (Dispolreg 007) were synthesized and utilized to mediate/initiate NMP in both homogeneous and heterogeneous polymerization systems. The introduction of TPE groups decreased the C–O bond dissociation energy (BDE) of NH₂-TEMPO-St and led to more efficient NMP with a higher reaction rate, even at lower temperatures. Moreover, for both solution polymerization and miniemulsion polymerization, quantitative information of the polymerization process could be easily acquired with the naked eye without destroying the reaction system, by building the relationship between the increased photoluminescence (PL) intensity of the system and monomer conversion as well as the molecular weight (M_n).