Star Synthesis Using Macroinitiators via Electrochemically Mediated Atom Transfer Radical Polymerization

Electrochemically mediated atom transfer radical polymerization (eATRP) was investigated for synthesis of star polymers using macroinitiators (MIs), achieving high star yield with low Cu catalyst loading (similar to 100 ppm, w/w). The arm first method, using MIs, is one of the most robust procedures for star polymer synthesis. During the polymerization, MIs can react with cross-linkers (divinyl or multivinyl compounds) for initial chain extension followed by the cross-linking reaction. The MIs can be transformed to arms of the star, and the cross-linker can form the star core. In this study, poly(ethylene oxide) (PEO, M-n = 2000) based MIs (PEO MIs) were prepared, and the chain-end functionalities were confirmed by H-1 NMR analysis. The ATRP functionalized PEO MIs were then used for the star synthesis by reacting with ethylene glycol diacrylate cross-linkers. Various experimental conditions were conducted for optimizing star formation, including MI concentration, MI to cross-linker molar ratio, and applied potential (E-app).