The only exception shows A-PentOzi-A. The molecular weight determined by 1 H NMR is lower than the estimated molecular weight and the SEC elugram shows a bimodal distribution of the polymer and higher dispersity of 1.4, compared to the other polymers. This could result from the modified polymerization procedure used for this reaction, as the polymerization of the hydrophobic PentOzi block did not show any progress in the 1 H NMR after 1 week at 120 °C.