TY - JOUR A1 - Robinson, J.W. A1 - Secker, C. A1 - Weidner, Steffen A1 - Schlaad, H. T1 - Thermoresponsive poly(N-C3 glycine)s T2 - Macromolecules N2 - Ring-opening polymerization of N-substituted glycine N-carboxyanhydrides (NCAs) was applied to prepare a series of well-defined poly(N-C3 glycine)s (C3 = n-propyl, allyl, propargyl, and isopropyl), polypeptoids, with molecular weights in the range of 1.8–6.6 kg mol–1. Poly(N-isopropyl glycine), a previously unreported polypeptoid, could be obtained by bulk polymerization of the corresponding NCA in the melt. The samples were characterized by spectroscopy (NMR and FT-IR), size exclusion chromatography (SEC), and matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy (MALDI–ToF MS). The polymers could be dispersed in water up to 20–40 g L–1; the poly(N-propargyl glycine) was not soluble in water. Turbidity measurements of the three water-soluble polypeptoids illustrated cloud point temperatures dependent on structural and electronic properties of the side chain. The cloud point temperatures were found to increase in the order C3 = n-propyl (15–25 °C) < allyl (27–54 °C) < isopropyl (47–58 °C). Long-term annealing of the aqueous solution of poly(N-{n-propyl} glycine) and poly(N-allyl glycine) above the cloud point temperature resulted in the formation of crystalline microparticles with melting points of 188–198 and 157–165 °C (differential scanning calorimetry, DSC), respectively, and rose bud type morphology (scanning electron microscopy, SEM). PB - American Chemical Society CY - Washington, DC PY - 2013 UR - https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/27696 AN - OPUS4-27696 SN - 0024-9297 SN - 1520-5835 VL - 46 IS - 3 SP - 580 EP - 587 AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany