TY - JOUR A1 - Lutz, J.-F. A1 - Kubowicz, St. A1 - Baussard, J.-F. A1 - Thünemann, Andreas A1 - v. Berlepsch, H. A1 - Laschewsky, A. T1 - Multicompartment Micelles Obtained via the Self-Assembly of a Well-Defined Triblock Macrosurfactant Prepared by RAFT Polymerization KW - Micelles KW - Living polymerization KW - RAFT KW - Block copolymers PY - 2005 SN - 0032-3934 VL - 46 IS - 2 SP - 297 EP - 298 PB - American Chemical Society CY - Newark, NJ AN - OPUS4-10534 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kubowicz, St. A1 - Baussard, J.-F. A1 - Lutz, J.-F. A1 - Thünemann, Andreas A1 - v. Berlepsch, H. A1 - Laschewsky, A. T1 - Multicompartment Micelles Formed by Self-Assembly of Linear ABC Triblock Copolymers in Aqueous Medium KW - Small-angle x-ray scattering KW - Micelles PY - 2005 U6 - https://doi.org/10.1002/anie.200500584 SN - 1433-7851 SN - 1521-3773 SN - 0570-0833 VL - 44 SP - 5262 EP - 5265 PB - Wiley-VCH CY - Weinheim AN - OPUS4-10537 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Laschewsky, A. A1 - Mertoglu, M. A1 - Kubowicz, S. A1 - Thünemann, Andreas T1 - Lamellar Structured Nanoparticles Formed by Complexes of a Cationic Block Copolymer and Perfluorodecanoic Acid N2 - A double hydrophilic block copolymer was synthesized by controlled free radical polymerization, namely by the RAFT method, from a poly(ethylene oxide) macromonomer and a cationic acrylate. Stoichiometric complexes with sodium decanoate and with sodium perfluorodecanoate were prepared by self-assembly. Both complexes are soluble in water forming core-shell nanoparticles with hydrodynamic radii of 54 and 22 nm, respectively, and neutral potentials. The complex containing decanoate decomposed upon dilution, while the complex with perfluorodecanoate is stable even against dialysis and in salt solution. Only the nanoparticles containing perfluorodecanoate show a strong contrast in small-angle X-ray scattering (SAXS). It is produced from their cores that have an elliptical shape (short axes = 8.5 nm, long axis = 23.3 nm) and a sharp density transition to the shell. The cores exhibit an internal lamellar structure with a long period of 3.65 nm consisting of fluorocarbon rich lamellae (d1 = 3.00 nm) and lamellae enriched in ionic groups (d2 = 0.65 nm). These fluorinated nanoparticles coexist in physiological buffer with human serum albumin and fibrinogen without inducing aggregation. Moreover, the content of -helix of these serum proteins increased when in solution with the fluorinated nanoparticles. KW - Small-angle X-ray scattering (SAXS) KW - Block-copolymers KW - Polymeric nanoparticles KW - Protein secondary structure PY - 2006 U6 - https://doi.org/10.1021/ma061573k SN - 0024-9297 SN - 1520-5835 VL - 39 IS - 26 SP - 9337 EP - 9345 PB - American Chemical Society CY - Washington, DC AN - OPUS4-14392 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fandrich, Nick A1 - Falkenhagen, Jana A1 - Weidner, Steffen A1 - Staal, B. A1 - Thünemann, Andreas A1 - Laschewsky, A. T1 - Characterization of new amphiphilic block copolymers of N-vinylpyrrolidone and vinyl acetate, 2 - chromatographic separation and analysis by MALDI-TOF and FT-IR coupling N2 - PVP-block-PVAc block copolymers were synthesized by controlled radical polymerization applying a RAFT/MADIX system and were investigated by HPLC and by coupling of chromatography to FT-IR spectroscopy and MALDI-TOF MS. Chromatographic methods (LACCC and gradient techniques) were developed that allowed a separation of block copolymers according to their repeating units. The results of the spectroscopic and spectrometric analysis clearly showed transfer between radicals and process solvent. With the use of hyphenated techniques differences between main and side products were detected. In agreement with previously published results, obtained by NMR, SEC, static light scattering and MALDI-TOF MS, our data proved a non-ideal RAFT polymerization. KW - Amphiphiles KW - Block copolymers KW - Liquid chromatography KW - MALDI KW - Reversible addition fragmentation chain transfer (RAFT) KW - Liquid adsorption chromatography at critical conditions KW - Gradient chromatography KW - MALDI-TOF mass spectrometry KW - Hyphenated techniques KW - Mechanism of polymerization PY - 2010 U6 - https://doi.org/10.1002/macp.201000044 SN - 1022-1352 SN - 1521-3935 VL - 211 IS - 15 SP - 1678 EP - 1688 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-22012 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fandrich, Nick A1 - Falkenhagen, Jana A1 - Weidner, Steffen A1 - Pfeifer, Dietmar A1 - Staal, B. A1 - Thünemann, Andreas A1 - Laschewsky, A. T1 - Characterization of new amphiphilic block copolymers of N-vinyl pyrrolidone and vinyl acetate, 1 - analysis of copolymer composition, end groups, molar masses and molar mass distributions N2 - New amphiphilic block copolymers consisting of N-vinyl pyrrolidone and vinyl acetate were synthesized via controlled radical polymerization using a reversible addition/fragmentation chain transfer (RAFT)/macromolecular design via the interchange of xanthates (MADIX) system. The synthesis was carried out in 1,4-dioxane as process solvent. In order to get conclusions on the mechanism of the polymerization the molecular structure of formed copolymers was analysed by means of different analytical techniques. 13C NMR spectroscopy was used for the determination of the monomer ratios. End groups were analysed by means of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. This technique was also used to determine possible fragmentations of the RAFT end groups. By means of a combination of size exclusion chromatography, 13C NMR and static light scattering molar mass distributions and absolute molar masses could be analysed. The results clearly show a non-ideal RAFT mechanism. KW - Amphiphiles KW - Block copolymers KW - Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS) KW - N-vinyl pyrrolidone KW - Reversible addition/fragmentation chain transfer (RAFT) PY - 2010 U6 - https://doi.org/10.1002/macp.200900466 SN - 1022-1352 SN - 1521-3935 VL - 211 IS - 8 SP - 869 EP - 878 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-21905 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -