Professur für Makromolekulare Chemie, Department Chemie, Technische Universität Dresden Polypeptoids from N-Substituted Glycine N-Carboxyanhydrides: Hydrophilic, Hydrophobic, and Amphiphilic Polymers with Poisson Distribution Corinna Fetsch , Arlett Grossmann, Lisa Holz, Jonas F. Nawroth, and Robert Luxenhofer Ring-opening polymerization (ROP) of N-Carboxyanhydrides By ROP, a wide variety of polypeptides and polypeptoids (N-substituted polyglycines, POI) can be obtained [1]-[3] . We recently presented the preparation and characterization of non-ionic hydrophilic, hydrophobic, and amphiphilic polypeptoids. At that point, we emphasized on the polymerization kinetics to verify the livingness of the ROP of N- substituted N-carboxyanhydrides and prepared amphiphilic block copolymers [4] . Here, we want to summarize results, which illustrate how robust the ROP of N-substituted NCAs is [5] . The synthetic versatility and definition with main chain degradability makes POI attractive as next generation biomimetic (bio)materials. References Acknowledgement This poster is based on work supported by Award No. KUK-F1-029-32, made by King Abdullah University of Science and Technology (KAUST). Chain extension of Polysarcosine Figure 5. Schematic representation of chain extension of polysarcosine Figure 6. MALDI-ToF mass spectra of the multiblock polysarcosine samples (block IDs 1 through 10). Figure 7. Gel permeation chromatography elugrams of the multiblock polysarcosine samples (block IDs 1 through 10) prepared in this study. Each elugram, starting from P(Sar) 10 represents the macroinitiator for the polymerization of the subsequent polymer. Table 1. Analytical Data of the polysarcosine including all polymerization steps. block ID M theo. a [kg/mol] M n b [kg/mol] Ð b M n c [kg/mol] Ð c M n d [kg/mol] 1 0.82 0.58 1.52 0.78 1.07 - 2 1.53 1.15 1.26 1.46 1.04 - 3 2.23 1.85 1.20 1.88 1.03 - 4 2.91 2.66 1.14 2.42 1.02 - 5 3.55 3.35 1.12 2.81 1.02 - 6 4.14 4.13 1.08 3.37 1.02 - 7 4.70 4.64 1.08 3.75 1.01 - 8 5.24 5.14 1.09 4.11 1.01 - 9 5.76 5.46 1.11 4.43 1.01 - 10 6.25 5.96 1.10 4.89 1.01 5.72 a As calculated from [M] 0 /[I] 0 . b As determined by gel permeation chromatography. c As calculated from Gauss distribution fitted to MALDI-ToF mass spectra. d As determined by end-group analysis from 1 H NMR spectroscopy in D 2 O (signal intensity of aromatic protons of benzylamine-initiator vs main-chain and side-chain signal intensity). The molar masses increase steadily with the sequential monomer addition with no evidence of chain transfer events or termination of chains throughout the entire experiment. extraordinary robustness of ROP Polypeptoids from N-Substituted Glycine N-Carboxyanhydrides Figure 1. Schematic representation of prepared homo and block copolypeptoids. Figure 2. MALDI-ToF mass spectra (H + doping, matrix dithranol) poly(N-n- propylglycine) 25 with an overlay of the respective Gauss (red curve) and Poisson distribution (blue curve). (1) Kricheldorf, H. R. Angew. Chem. Int. Ed. 2006, 45, 5752. (2) Deming, T. J. Adv. Polym. Sci. 2006, 202, 1. (3) Hadjichristidis, N.; Iatrou, H.; Pitsikalis, M.; Sakellariou, G. Chem. Rev. 2009, 109, 5528. (4) Fetsch, C.; Grossmann, A.; Holz, L.; Nawroth, J. F.; Luxenhofer, R. Macromolecules 2011, 44, 6746. (5) Fetsch, C.; Luxenhofer, R. 2012, submitted. Kinetic Investigations of Sarcosine-NCA Figure 3. Linear pseudo-first order kinetic plots of the polymerization of Sar-NCA under different conditions. a) Dependency of the polymerization in N- methyl-2-pyrrolidinone (NMP) on the pressure at 20 °C (0.5 M, [M] 0 /[I] 0 =50). b) Comparison of polymerization of Sar- NCA in NMP (0.5 M, 50 mbar, 20 °C) with different initiator concentrations. c) Comparison of different monomers in NMP ([M] 0 /[M] t =50, 50 mbar, rt) and benzonitrile (BN; ([M] 0 /[I] 0 =50, 50 mbar, 20 °C). In all approachs linearity up to high conversions. Polysarcosine as Macroinitiator Figure 4. Gel permeation elugrams of the polysarcosine macroinitiator (PSar) with a second block of a) N-ethylglycine (PSar-b-EtGly) and b) N-n-propylglycine (PSar-b-nPrGly), respectively. The complete shift of signal towards lower elution times indicates high macroinitiator efficiency.