Mangold C.,Graduate School Materials Science in Mainz |
Mangold C.,Johannes Gutenberg University Mainz |
Dingels C.,Johannes Gutenberg University Mainz |
Obermeier B.,Johannes Gutenberg University Mainz |
And 2 more authors.
Macromolecules | Year: 2011
Introduction of highly reactive vinyl ether moieties along a poly(ethylene glycol) (PEG) backbone has been realized by copolymerization of the novel epoxide monomer ethoxy vinyl glycidyl ether (EVGE) with ethylene oxide (EO). A series of copolymers with varying structure (block and random) as well as EVGE comonomer content (5-100%) with molecular weights in the range of 3,900-13,200 g/mol and narrow molecular weight distributions (M w/M n = 1.06-1.20) has been synthesized and characterized with respect to their microstructure and thermal properties. The facile transformation of the vinyl ether side chains in click type reactions was verified by two different post polymerization modification reactions: (i) thiol-ene addition and (ii) acetal formation, employing various model compounds. Both strategies are very efficient, resulting in quantitative conversion. The rapid and complete acetal formation with alcohols results in an acid-labile bond and is thus highly interesting with respect to biomedical applications that require slow or controlled release of a drug, while the thiol-ene addition to a vinyl ether prevents cross-linking efficiently compared to other double bonds. © 2011 American Chemical Society.
Steinbach T.,Graduate School Materials Science in Mainz |
Steinbach T.,Max Planck Institute for Polymer Research |
Steinbach T.,Johannes Gutenberg University Mainz |
Ritz S.,Max Planck Institute for Polymer Research |
Wurm F.R.,Max Planck Institute for Polymer Research
ACS Macro Letters | Year: 2014
A small difference brings high control: In poly(phosphonate)s a stable carbon-phosphorus linkage attaches a side chain to a degradable poly(phosphoester)-backbone. A novel cyclic phosphonate monomer was developed to generate water-soluble aliphatic poly(ethylene methylphospho-nate)s. The monomer is accessible via a robust three-step protocol that can be easily scaled-up. Polymerization was initiated by a primary alcohol, mediated by 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in less than 2 h at 0 C. The molecular weight distributions were monomodal and very narrow (below 1.1) in all cases and molecular weights up to about 20000 g/mol have been prepared, proving the living nature of this polymerization. The resulting polymers were characterized in detail via NMR spectroscopy, size exclusion chromatography, and differential scanning calorimetry. Also, the reaction kinetics have been evaluated for several monomer/initiator ratios and found to guarantee a living behavior in all cases superior to other poly(phosphate)s reported earlier. The polymers are all highly water-soluble without a lower critical solution temperature and are nontoxic against HeLa cells. © 2014 American Chemical Society.
Spirin L.,Graduate School Materials Science in Mainz |
Spirin L.,Leibniz Institute of Polymer Research |
Kreer T.,Leibniz Institute of Polymer Research
ACS Macro Letters | Year: 2013
By means of molecular dynamics simulations we provide evidence for pronounced counterion immobilization in strongly compressed polyelectrolyte- brush bilayers, where the counterions represent the vast majority of mobile solvent particles. As a consequence, hydrodynamic effects are strongly suppressed and semidilute bilayers can respond to shear motion like electrically neutral bilayers at melt density. For large, time-independent shear rates, γÌ‡, the shear force scales as f(γÌ‡) ∼ γÌ‡0.69, in agreement with scaling theory. In this regime, polyelectrolyte-brush bilayers can stabilize highly nonstationary processes, such as the instantaneous inversion of the shear direction. The absence of hydrodynamic flow leads to a suppression of the overshoot for the shear force, which is found for electrically neutral bilayers with the same molecular parameters. We suggest that nature uses this mechanism to optimize biolubrication, for instance in synovial joints. © 2012 American Chemical Society.
Klinker K.,Graduate School Materials Science in Mainz |
Klinker K.,Johannes Gutenberg University Mainz |
Barz M.,Johannes Gutenberg University Mainz
Macromolecular Rapid Communications | Year: 2015
Polypept(o)ides combine the multifunctionality and intrinsic stimuli-responsiveness of synthetic polypeptides with the "stealth"-like properties of the polypeptoid polysarcosine (poly(N-methyl glycine)). This class of block copolymers can be synthesized by sequential ring opening polymerization of α-amino acid N-carboxy-anhydrides (NCAs) and correspondingly of the N-substituted glycine N-carboxyanhydride (NNCA). The resulting block copolymers are characterized by Poisson-like molecular weight distributions, full end group integrity, and dispersities below 1.2. While polysarcosine may be able to tackle the currently arising issues regarding the gold standard PEG, including storage diseases in vivo and immune responses, the polypeptidic block provides the functionalities for a specific task. Additionally, polypeptides are able to form secondary structure motives, e.g., α-helix or β-sheets, which can be used to direct self-assembly in solution. In this feature article, we review the relatively new field of polypept(o)ides with respect to synthesis, characterization, and first data on the application of block copolypept(o)ides in nanomedicine. The summarized data already indicates the great potential of polypept(o)ides. Polypept(o)ides are hybrid materials consisting of polypeptides and polypeptoids. In this feature article, the synthetic methods, polymer properties, self-assembly in solution, and first applications as nanomedicines are summarized. Moreover, future perspectives for polypept(o)ides are outlined. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Golde S.,Graduate School Materials Science in Mainz |
Golde S.,Johannes Gutenberg University Mainz |
Franke M.,Graduate School Materials Science in Mainz |
Schope H.J.,Graduate School Materials Science in Mainz
AIP Conference Proceedings | Year: 2013
We describe a new designed multispeckle correlation spectroscopy (MSCS) setup which uses a CCD-camera as optical detector. Due to the simultaneous detection of many coherence areas (speckles) we get a much better statistic than in standard dynamic light scattering (DLS) measurements. Furthermore the intermediate scattering function (ISF) for nonergodic samples can be determined from one measurement. A special feature of our setup is the direct imaging of the scattering volume on the CCD-camera. Therefore every speckle can be connected to its origin scattering volume. This space-resolution gives us the possibility to probe the particle dynamics at different sample positions. Further, we present frequency distributions of the intensity autocorrelation functions for a fluid and a metastable sample. © 2013 American Institute of Physics.