The polymerization and work-up procedures were carried out as described previously. Briefly, 1 eq. of initiator (MeOtF) was added to a dried and argon flushed flask and dissolved in the respective amount of solvent (PhCN). The monomer was added and the reaction mixture was heated to 110°C (POx) or 120°C (POzi) for approximately 4-6 hours. Reaction progress was controlled by 1 H-NMR spectroscopy. After complete consumption of the monomer, termination was carried out by the addition of 3 eq. of Boc-pip and the mixture was stirred at 50°C for additional 4 hours. PhCN was removed under reduced pressure. In the case of four hydrophobic homopolymers (pBuOx, pPentOx, pPrOzi and pBuOzi), after PhCN removal, the thick polymer mass was dissolved in chloroform and extracted three times against water followed by chloroform removal under reduced pressure.