Summary: Cylindrical polymer brushes from PSSE and PSSD have been synthesized by a ‘grafting from’ approach by ATRP in solution. Starting from macroinitiators with 570 and 1 600 repeat units, and 10–100% reactive site density, PSSD brushes with 10–40% grafting density and PSSE brushes with 10–100% grafting density are obtained. The brushes have been characterized by 1H NMR spectroscopy, GPC‐MALLS, analytical ultracentrifugation, AFM, and TEM.