was also used to further investigate the structure of polyacrylate produced by photo-LRP mediated by organocobalt porphyrins. Figure 9 shows the MALDI-TOF-MS spectrum of the PMA sample (Mn,GPC = 4200, Mw/Mn = 1.11) obtained with the ratio of [MA]0/[(TMP)Co-CO2CH3]0 = 200 under visible light irradiation at room temperature. The results indicated that there were two main series of peaks with regular interval of 86.04, corresponding to the monoisotopic mass of MA repeating unit. The experimental isotopic mass values of
the main peak series agreed well with the theoretical values, as shown in the upper part of Figure 9. The (TMP)Co terminal group might undergo chain transfer reaction24 under the MALDI conditions due to lack of free monomers so that fragmented polymer chain was observed.