Clickable Stars by Combination of AROP and Aqueous AGET ATRP

Abstract

A series of star-shaped poly(ethylene oxide) (PEO) with azide groups at the end of each arm were synthesized by combination of anionic ring-opening polymerization (AROP) and aqueous activators generated by electron transfer for atom transfer radical polymerization (AGET ATRP). First, α-azido, ω-hydroxy heterofunctional PEOs were prepared by AROP of ethylene oxide (EO) using tetrabutylammonium azide as initiator and triisobutylaluminum as catalyst. Then, a clickable PEO ATRP macroinitiator, α-azido, ω-bromoisobutyryl heterofunctional PEO, was synthesized by an esterification of the ω-hydroxy end group with 2-bromoisobutyryl bromide. Finally, an AGET ATRP of ethylene glycol diacrylate (EGDA) was carried out in water using the α-azido, ω-bromoisobutyryl heterofunctional PEOs as macroinitiator and surfactant. The absolute molecular weights of the products were characterized by static laser light scattering in water. Azide PEO stars with Mw = 6.58 × 106 and average 309 arms were obtained using azide PEO macroi...