Starting from different core sizes of [PEG-NH2]4, α-Bromoisobutyryl bromide was used for end group modification of all four arms, achieving amide-based macroinitiators for atom transfer radical polymerization (ATRP) and single electron transfer living radical polymerization (SET-LRP). As the deprotection of tBAMA is performed under acidic conditions, an amide macroinitiator was chosen. This functionality leads to higher stability towards hydrolysis in comparison to typically reported ester counterparts. This concept was already successfully used for linear block copolymers. 17 1 H-NMR spectroscopy shows a quantitative modification of the amines when the corresponding methyl groups are compared to the PEG backbone (Figure ).