Fig. 4. Schematic illustration of the block-wise growth of poly (HEMA) brush due to multiple initiations and terminations (a). Multiple initiations and terminations, caused by repeated switching of CRM and IRM solutions, recorded in situ by QCM during SI-ATRP of 1 : 1 HEMA/water mixture with 100% relative catalyst concentration at 25 °C (b). Available initiating sites calculated from the slopes of the polymerization profiles after each initiation (c).
